I would suggest you go ahead and take this boy, for fear he would fall into the wrong hands.....greeders! If it is not working out to keep him you could then either rehome him yourself or surrender him to a rescue.
My Ruby is barely 3 lbs. I've got little dogs here, from her size to 8 lbs. They do all play together and Ruby does try to get involved, but I have to be careful with the gang (not to get too wild) when she is playing with them.
Definitely get him neutered, no it's not too late. He may still mark but possibly not, our little poodle will still mark outside but never inside. Be certain to have pre-op bloodwork done before neutering.
Good luck.....he is adorable!!!
