Well, as all ISBEs are also from the All, and we are all the universe experiencing itself, is there really such a thing as evil or good? Evil is in the eye of the beholder.
I prefer the concept of yin and yang from Taosim, in which "bad" is a *judgement* based on your goals.
Conversely, if you fight a parasite off and it dies of starvation, was it just following it's nature so are you evil now? Me, I think we have a right to defend ourselves, and this is also simply part of experiencing the universe.
When you break an egg to make an omelette you might be pretty evil as far as the egg's concerned. But for you, you're not evil, you're just making an omelette. Do you need to evolve so you don't have to make omelettes any more? ...Maybe. But it is what it is at the stage you're at in your evolution. God created you and chickens and omelettes after all.
"Do young ISBEs start to incarnate into animals?" ...
I feel like being an animal is already quite advanced. New spirits might be more like, elementals to start with, something to get a handle on being a separated consciousness in the first place.