I forgot that was a thing until I accidentally clicked on one of them. The minion battles are fun but I have a few questions.

Is them leveling up a permanent thing even if I remove them from the zoo? Do the stat gains have a purpose outside of the zoo? And why are some minions stat-less?

that site feature was discontinued long ago so minions released after that won't have a status removing the minion will reset the level minion levels won't affect anything outside the zoo