Playing as Lorien elves, after a while I got a quest to take Treebeard's village. I did this, but had to kill Treebeard to do it. That seems an odd way to make friends with the Ents?

So then they want to be independent, granted. Later, the Ents arrive to help me. So I add them to my army and go conquering. Then they say that they are leaving suddenly. Ah, I didn't have any hint about that. Except, they don't. They are still in my army and I still have full control of them.

Later I get another unit, which I suspect will act the same?

Can Ent units be replenished? I suspect not, which would be lore. Just checking.

Is this something that can or should be looked at? They are subtle problems.