Questions about Terralith pregen

I was thinking of using Terralith for a survival server, but I’ve seen that pre-generating the world is better to avoid generation issues. What’s the best way to do it? If I want to keep the same mobs and behaviors from the datapacks, do I need to keep them in the world, or would removing them to save resources cause issues?

I was also thinking of adding other worldgen plugins like Incendium, Nullscape, Structory, etc. Is it fine to mix them, or is there anything I should consider first?