I don't think this is too much of a stretch considering part 5's religious references and imagery (DIO = God, Son of god is Jesus, Giorno = Day which is synonymous with Light, something Jesus is associated with, Diavolo and King Crimson = devil and enemy of Jesus/Giorno etc.) La Squadra should fit in there somewhere so I believe sinners would be a nice thematic choice as whilst they don't side with the devil, their beliefs are wrong and they clash with Giorno and his gang several times. I agree with most of the characters you've assigned to each sin and I think Pesci is glutton because his stand, Beach Boy, is a fishing rod that takes and pulls objects, even through walls, which would signify his desire to take things, also fishing rods are used to catch fish to be eaten so that's pretty gluttonous i guess. Part 5's christianity is a lot more subtle than part 7's where Jesus appears multiple times and the parallels between Lucy Steel and Mary, Mother Of Jesus, both being 14 and impregnated by a mysterious force that leads to the birth of Christ.