I'm not convinced that what the Corinthians were doing had anything to do with Gnosticism. There is some evidence that Gnostic ideas were circulating among Christian communities almost from the outset; certainly it was so by the time the epistles of John and Jude were written. But the Corinthians specifically do not appear to have been influenced by Gnosticism. If anything, they were displaying the influence of ecstatic pagan practices of the sort which flourished in Asia Minor -- esoteric 'ecstatic' practices associated with the cults of Cybele and Dionysos and which later influenced the Montanists and the Sufi dervishes.

Whether the Corinthians were employing ritual transvestism is a conjecture, but an interesting one. The worship of Cybele and Dionysos certainly involved, on occasion, ritual transvestism. The Montanists edged into the arena of androgyny too. Whatever the case, the Corinthians must have been doing something in their worship that distressed Paul so that he felt he had to admonish them to ensure that men looked like men and women like women.

My instinct is that Paul's instruction about gifts of the spirit was meant to steer the Corinthians away from ecstatic practices associated with paganism and instead channel their charisma into something that suited his Christian sensibilities. But I haven't examined the matter very closely, yet.