Nice ideas.
I think the Incarnate sticking around permanently might be a good idea. There could be a "Change Form" spell (1 AP, 1 Turn Cooldown) which changes the Incarnate to the type of surface it is standing on. If it attacks something, that is considered an attack by the Summoner. A permanent Incarnate might also create another potential trade-off: it would allow the Summoner to forget the Summon Incarnate spell out of combat to make room for another slot, but that will mean you can't re-summon it in combat if it dies.
A "Totem Mark" spell might be a good idea too. Let's say 2 AP, it lasts for 2-3 turns, and all Totems will try to hit the enemy. Maybe as an additional effect, there will be some kind of damage buff for the totems OR it will damage enemy armor (physical and magical) for some amount).
A downside can be that the totems won't care if the enemy is in line of sight or not, and they certainly won't care if teammates are in the path.
