He sounds like a normal young male, starting to be territorial. Is he intact, or neutered? Sometimes that makes a difference. And I agree that the whole "alpha" and dominance theories are rather outdated. We just work at having happy dogs, and they seem to sort things out pretty well on their own. All the furniture belongs to all of us, no need to claim any of it!
As for rain, get a big umbrella and go out with him, keep him under the umbrella if he will, and then reward well for going to the bathroom, get him back in and dry him off and make a game of it. He won't necessarily like it but you will have a clean dry house.
Basenjis (in my experience) are much easier if you just let them think it's their idea and then they will do what you want! Much more fun to outsmart your basenji than to try and 'out-alpha' him, that is a long and unrewarding relationship for everyone, IMHO.
Set him up for success and reward accordingly. Don't disturb a sleeping animal of any sort, some wake up very badly, nothing personal! Walk and praise, and for a young basenji, pulling like a demon is pretty natural and requires a lot of work to improve .(age helps, my oldsters hardly pull at all!)