1. Nicolatian's Teachings only lasts as long as the enhancement stays. If the enhancement leaves, the hero returns to its owner.
2. Unity is "your", which is "own and control". Taking a hero with Nic's Teachings does not stop unity.
3. Yes. The unity is "if all your X are Y", not "if none of your X are Z" - even though Humble is NT, it is also OT and so still works for Covet.
4. I believe initiative in a stalemate/mutual goes to whoever put the last card in battle. Since the dominant didn't go to battle, the same person still has initiative.
5. I believe so, yes.