The whole "animals" thing is just how the MC refers to her group of 5 friends.

Rin, She would include herself in that naming, remember their clans are all named after an animal, black tortoise, white tiger etc. and they are all the heirs so hence calling them as the animals instead of the more wordy 'heirs to the clans of a, b, c and d). Also there could be a reference to their 'beastly' nature as an admiration of their strength. In these novels they often refer to an op person as a beast. So multiple levels of meaning. (Also I suspect a bit of laziness and saving on typing. But we can't blame author/translator for that).

omfg i want her to come out as her beautiful self :"(

HerHer beautiful self, since the identity she used in practicing warlock is her orig. self

Don't think it means literally killed, just defeated really quickly (like one-shot, etc)

In Chinese novels you see "killed to" alot. Basically means a quick fierce charge. Might be something similar. Some wordings are hard to translate it seems. Possibly it's just describing his style rather than actual deaths.