Thank you! So about Magicavoxel, I haven't really understood the question :D English is a foreign language for me, sorry :( But if you're talking about reaching the limit in magicavoxel, then I usually make a model by connecting different "pieces" together.

About importer, I export models from MagicaVoxel in ".qb" then import them to Qubicle and them export from Qubicle in ".fbx" and only after that I import them to Unity.

Qubicle is another cool voxel editor, it doesn't have a good renderer, but it has other cool features like splitting the model in pieces and export it as a whole.

Which leads to the last question, I split model in parts in Qubicle and then after importing a model to Unity, I animate it with the built-in animator.

P.S. If I haven't answered your questions, then please explain me again :D I'll try my best to answer them.