Evidently no, there is no such concern in the ancient accounts of this story. Like many other extraordinary elements of these tales, such as Orpheus charming his way into the land of the dead by the power of his music, the assumption is simply that such things must have been possible.
Book 5 of Statius' Silvae describes Eurydice as having a funeral pyre, thereby implying that she was indeed cremated. As far as I've been able to find, however, there is no ancient mythography expressing any difficulty with the idea of anyone being resurrected—if a divinity who wants to enact this resuscitation should grant its occurrence—regardless of the condition of the body of the deceased.
Interestingly, incidentally, fire is often an important medium used by the gods in order to transform a mortal into an immortal. Part of what makes Dionysus the special son of a divine father and a mortal mother is that, even before he was born, he was bathed in the same flames that killed his then-pregnant mother Semele whereupon he completed his gestation while sewn up into his father's thigh. This unorthodox procedure essentially rendered him immortal.
As for Semele herself, Book 8 of Nonnus' Dionysiaca says that, as she was being raised from the Underworld in order to be made into the goddess Thyone, she was given a "new body" which was "bathed in the purifying fire". In his request to retrieve his wife from the dead, Orpheus does not seek for her to become immortal in the process of her proposed resurrection, so presumably the new body she would have acquired would not have required a baptism of flames.
Capaneus, For Example
There are indeed instances in this mythology of the cremated dead being restored to mortal bodily life, but we are not provided with the mechanics of this procedure, either because it was simply taken for granted that it was achievable by divine powers (such as when Odyssey 10.306 says that certain things are difficult for mortal men, but that "with the gods all things are possible"), or because records of such details have not survived into our time.
In the story of the war of the Seven Against Thebes, one of the city's seven attackers is a virtually gigantic Argive warrior named Capaneus, who gets blasted dead by a thunderbolt from Zeus while he scales one of the walls of Thebes. The fire kindled by the lightning-strike is so huge that days after Capaneus' demise, live flames are still consuming his body to the extent that there is no need to kindle his funeral pyre, which lights up as soon as he is set upon it. One wonders if even his bones could have survived such intensity.
Capaneus is among the individuals said to have been resurrected from the dead by Asclepius before the latter became a god. Philodemus mentions that this story is told in Stesichorus' now-lost play Eriphyle. Sextus Empiricus informs us of this as well, without offering any detail, and we know that in the Classical period a certain Timesitheus wrote a bunch of plays, none of which are currently extant. One of these is entitled Capaneus, and perhaps might have told us what this resurrection looked like mechanically speaking.
Blood and the Threads of Fate
Aeschylus' Agamemnon alludes to the resurrections performed by Asclepius, who was killed by Zeus for bestowing this gift upon the dead:
But a man's blood, once it has first fallen by murder to earth in a
dark tide—who by magic spell shall call it back? Even he who possessed
the skill to raise from the dead—did not Zeus make an end of him as
This could be interpreted figuratively as more poetic language, or perhaps it could be taken to mean that the life is (literally) in the blood (such as in Leviticus 17:11), and so the resurrection mechanism involves the lost blood of the deceased somehow being reconstituted to form the (re)new(ed) body.
The more mystical aspect of this process is touched upon in Book 6 of Ovid's Fasti, wherein Theseus' son Hippolytus is resurrected by Asclepius. In so doing, this healer hero is said to be re-spinning the broken thread of the life of Hippolytus, against the will of Clotho, the fate-goddess responsible for spinning the threads of people's lives.
The same passage also describes how mangled the dead man's body is upon the request for him to be restored to life. This is not a matter of much concern to Asclepius, who promises to "restore the pious youth to life all unscathed," which he does indeed manage to do by placing some herbs on his chest and chanting a spell.