Odyssesy's need for a disguise his because of his trials he needs to complete to go back to ithaca, Posideon has a serious grudge against Odyssesy's which forces him to start these harsh trials so he can be ready when he makes he's return to ithaca in his disguise.

Calypso island is very bizarre and full of life, i think that Calypso's island represents greed because the options that Calypso give to Odyssesy's are very fruitful and extravagant and that if he stays on this island with her he can have it all and not have to worry about anybody else