Ok, quick question here, If a necromancer gets his hands on a PC corpse, can he, with the player owning the PCs consent, turn the corpse into a zombie/undead?

Mechanically, I am unsure if this system is fully finished yet. Our death system is extremely complicated, and a very complicated (yet awesome) animation system for PCs was being worked on, but I don't think it's completely finished yet. So my guess is that you can not technically animate PCs at this time, although it's worth noting you can animate some other things (like deep lizards, if you find/buy the right corpse).

You definitely don't need a player's OOC permission, though.

In some specific situations, a DM may assist you with this even if the scripts aren't done completely.