So hopefully that last one is the other adult and you'll be done with your issue after your hunting trip
Unfortunately, they left a nice set up if another young pair finds your pond next summer. They'll be easier to remove (hopefully) if that happens though, a beaver pushing 50 pounds has been around a while.
I don't know for sure on the cattails but I would think most of what they use in the summer goes right back in the winter. Could be wrong there though.