Yeah, definitely a Vampire. They can shapeshift, so no significant opening in the trees is fine.
And it would not be the first time a vampire decided they wanted a karak for themselves.
Possible, but they have a hard time staying in the world normally. This doesn't feel like the kind of thing they would be doing with their limited time frame. Or more accurately I think there aren't enough moving parts for this to be one of their plots they are enacting while in the world. They'd be more likely to be manipulating other groups into doing this.