If Vincent isn't on the battlefield when its last ability resolves, use its power as it last existed on the battlefield to determine whether it deals damage to each other opponent
Each play booster can contain up to four total rares, so the theoretical highest number of rares you could open is 120 (or 144 for 2024 play booster boxes), though you should be playing both the lottery and lots of Sealed if youre that lucky
It can be improved with meta staples like Robin Hood Champion of Sherwood or Beast Tragic Hero
And the deck isn't even technically an Elf deck, but with 12 one drop mana making Elves, plus 4 Priests, and 4 Circles, you have 20 Elves that tap for mana, then flesh out your deck otherwise
Capitalism at its finest, I know, and for Final Fantasy MTG, "Market Price" is currently around $20-40 over MSRP, depending on what you're buying