In connection with A, it is remarkable that v.1 forms in the Vulgate the last verse of the preceding chapter, i.e. the last verse of Susanna. This arrangement may have been made from chronological reasons, possibly to escape an apparent difficulty; and in the LXX the verse is wanting altogether. Either plan, the attachment of the verse to Susanna, or its entire omission, has the effect of leaving the king in this piece nameless, and so solves the imagined difficulty of Cyrus and Daniel acting together as represented.
The text commented on by Theodoret offers the same solution in another form, viz. by transferring v.1 to the end of chap. xii., and so concluding the book. He thus introduces it: Houto plerosas ten apokalupsin epegagen ho prophetes kai ho basileus Astuages, k.t.l. Theodoret comments no further on Bel and the Dragon, though his remarks in other parts of the commentary shew that he favourably regarded it. See his observations on v.31, x.1.
The disappearance in one case, and the displacements in the others of this verse, evidently point to some uncertainty in early times as to its right connection. But the difficulties raised as to this verse even where it stands are not so serious as was once thought. As Ball says in loc., "The cuneiform records have thrown unexpected light on difficulties which were the despair of bygone generations of scholars," and quotes one which makes Astyages the captive of Cyrus. J. H. Blunt attempts to shew, not very satisfactorily, that the king of v.2 was Darius. A note in Husenbeth's Douay version, still less so, quietly says "Astyages, or Darius"!
It has also been suggested, with regard to this and difficulty C, that another Daniel is here intended, to be identified with the Daniel of Ezra viii.2 (Bissell).
The second difficulty, B, is raised by the asserted destruction of Bel's temple in v.22. Now this is said not to have been destroyed till Xerxes' return from Greece in 479. Even then Herodotus (I.183) merely says that he took' (elabe) a golden statue, and slew the protesting priest; Strabo, on hearsay, (XVI.1) and Arrian (Exp. Alex. VII.17), however, assert its destruction. But this forms a small obstacle, unduly magnified. Supposing Bel's temple to have been destroyed, as v.22 narrates, it is far from improbable that another temple may have been raised before Xerxes' arrival. The people were evidently attached to Bel's worship, as v.28 shews, notwithstanding the conviction of their king as to the truth of Daniel's God. It is noticeable that the LXX has no mention of the temple's, but only of the idol's, destruction; and that Th, according to the manuscript Q, has not hieron but naon in v.22.
A. Scholz entertains the strange opinion that this and other historic difficulties were purposely introduced by the writer: "Der Verfasser unserer Erzählung kennt sichtlich die Verhältnisse in Babylon, und hat seine Darstellung so eingerichtet, dass es einfach unmöglich ist, sie geschichtlich zu verstehen" (p.219). But this is a desperate expedient to support his view of the whole story being intended for a vision,' and it would be hard to find any parallel to such a proceeding on the part of the sacred writers. 
So far as Babylon is concerned, there is no indication of anything but a time of peace, which is quite in accordance with the supposed period of the narrative.
There is perhaps more difficulty, C, in making Habakkuk than in making Cyrus, a contemporary of the grown-up Daniel. Indeed, with the earlier date formerly assigned to Habakkuk, the difficulty seemed all but insuperable, except by postulating two Habakkuks or two Daniels. And, much as it may lack vraisemblance, either of those suppositions is of course within the bounds of possibility. So Trapp notes, rather sneeringly, on Hab. i.1: "Those apocryphal Additions to Daniel, which either are false, or there were two Habakkuks"; and J. H. Blunt, more seriously, to a similar effect on Hab. i.1 and Bel 33. Josippon ben Gorion (I.7) joins the whole story with the canonical history, but, as given by Delitzsch (op. cit. p.40), transposes, presumably from chronological motives, the den incident to the beginning of the story, "in ordine chronologico iudaicæ traditioni de Habacuci ætate se accommodantem." Josippon, around whom considerable obscurity hangs, is dated as of the eighth or ninth century in the Biog. Univ. art. Gorionides, Paris, 1857; but in Hastings' D. B. art. Bel and the Dragon, p.267b, c. a.d.940 is given as his time.
Habakkuk's prophecy is now dated as late as 600 (Driver in Hastings' D.B. art. Habakkuk; Kirkpatrick in Smith's D. B^2. art. Habakkuk, 1256b, says "not later than the sixth year of Jehoiakim"); and if Habakkuk prophesied in his youth, our story is not an impossible one. So Cornelius Jansen (Analecta, p.154), "Quapropter nihil obstabit quo minus idem Habacuc iam senex prandium in Babylonem detulerit," and he quotes a tradition of Isidore Hispalensis (de vit. Proph.) that Habakkuk lived to see the return from the Captivity, and two years after. Rosenmüller, quoted in a note on Hab. i.1 by Maurer (neither of whom were too partial to traditional views), thinks that the time of Habakkuk is consistent with the "vetus fama in apocryphis Danielis additamentis." He even places chap. iii, of Habakkuk under Zedekiah, though with this Maurer does not agree (cf. Henderson, Min. Proph., Introd. to Hab.).
Jamieson, Brown, and Faussett in their Commentary, Introd. to Hab. (1869), by no means inclined to favour the Apocrypha, say that Bel and the Dragon agrees with the notion of Habakkuk prophesying in Jehoiakim's reign.
G. A. Smith, however, in his Book of the Twelve Prophets, 1900, II.130, contents himself with calling it "an extraordinary story of Habakkuk's miraculous carriage of food to Daniel in the lions' den, soon after Cyrus had taken Babylon." But A. C. Jennings, in Bishop Ellicott's Comm. for English Readers, Introd. to Hab., pp.523-5, says: "The story, worthless in itself, nevertheless indirectly confirms the theory of date which we have accepted below" in these words, "Habakkuk's prophecy dates from the reign of Jehoiakim, not more than five years at most before the battle of Carchemish -- how much nearer that great event it is impossible to say." Dean Farrar also curiously observes, "Habakkuk's appearance in apocryphal legend (vv.33-39) shews the impression he had made on the mind of his people, and perhaps indicates his date as a contemporary of Daniel." (Minor Prophets in Men of the Bible' series, n.d., p.160).
Another instance of belief in the contemporaneity of Daniel and Habakkuk is afforded by Raymund Martini (c.1250) in his Pugio fidei (Paris, 1651, p.740): "Habacuc vero Prophetam fuisse contemporaneum Danieli inde colligitur ubi in Bereschit Rabba hoc modo scribitur de Joseph," he says before quoting a long passage from the B. R. on Gen. xxxvii.24. This passage is none other than a portion of Bel and the Dragon in Chaldee, and is headed without reserve as vdny'l. It proceeds with v.28 to the end: lchd yhvd'h hv' lyh v'ytknsv vvl'y l mlk'
tlk' lvyl tvd vltnyn' qtl v'thphkv lyv v'mryn chd. Then follows a Latin translation, after which Martini adds "Hucusque traditio," and, after quoting Hab. i.6, finishes his work.
Martini's good faith in quotation is defended by Neubauer in his Chaldee Tobit (Oxf, 1888, xviii. to xxiv.). He also identifies the Breshith Rabbah quoted with the Midrash Rabbah de Rabbah. The real Breshith is probably as early as the 4th century; but neither in the Venice edition of 1566, nor the Leipzig one of 1864, is the passage to be found under Gen. xxxvii. Cf. Payne-Smith's note, as to Martini's quotations, in Pearson on the Creed, Oxf.1870, p.306, where it is shewn that by Breshith Rabbah the book by Moses Haddarshan (of the 11th century) is sometimes meant. Etheridge states that only fragments of this book are extant (p.406). Delitzsch (de Habacuci Proph. vita atque ætate, Lips.1842, p.34) also defends Martini's sincerity, and says "Non dubito fore, ut fragmentum a Raymundo nobiscum communicatum aliquando in antiquis Genesis Rabba Codd., qui sane rarissimi sunt, inveniatur."
The fact incidentally brought out in the story that Habakkuk was not engaged in reaping, but was occupied in taking out food for the reapers, fits in well with the idea of his advanced age. Such a task might well be undertaken by one who was no longer strong enough for field labour. 
All these difficulties would, on other grounds, be deprived of much of their importance by the theory of A. Scholz, if that could be accepted as true. He regards the entire book of Daniel, including of course the Additions, as a series of apocalyptic visions (p.201). This he considers as the earliest explanation, supported by the heading horasis to each chapter of Daniel in A and some other MSS. But while removing one set of difficulties, this theory introduces others of a character at least as serious; and it is by no means easy to convince oneself that there is an "apocalyptic" tone about this or the other Additions. This remarkable theory cuts, rather than unties, such knots as are above noted, and carries with it to most minds a strange and improbable air.
 The phrase applied to the Additions in the Introd. to Daniel in the Speaker's Comm. (p. 216a), dvr phyvtyn if we take phyvt to mean 'poet,' would fall in with this view. J. M. Fuller does not make quite clear his source for this phrase.  Sozomen, H. E. vii. 29, says that Habakkuk's tomb was found at Keilah, kela, he prin keila . . . kath' en ho Abakoum (sic) heurethe. Now Keilah is mentioned in 1 Samuel 23.I as having threshing- floors worth robbing, and so presumably lay in a corn-growing district.
 Sozomen, H. E. vii. 29, says that Habakkuk's tomb was found at Keilah, kela, he prin keila . . . kath' en ho Abakoum (sic) heurethe. Now Keilah is mentioned in 1 Samuel 23.I as having threshing- floors worth robbing, and so presumably lay in a corn-growing district.