This has amazing potential and is probably one of THE most unique and thoroughly well implemented ideas i've seen on this site. Extremely interesting and stands out from the rest to be honest.
My one and only gripe is with the rarity for the legendary cards. I swear I spammed so many purchases and I haven't got a single one. Typical Gacha I suppose!
I dream of the idea of this being fleshed out into a full game. Think "Welcome To The Game" but with lolis and you're the invader. :)