My lab gets those fatty tumors also. We had one removed that was on his belly and rubbing on the floor so much it was getting raw and our vet was worried about infection. Other than that, we just let them alone. I'd get them checked out to be sure.
As for the leg/hip problems, Murphy has that, too. His hips were pretty bad, but we put him on food and treats with glucosamine and chondroitin in them. It's helped a lot. He moves a lot easier these days. He still has problems, but they are not as bad as before. Make sure he gets plenty of Omega-3's also. It seems that helps with the effectiveness of the glucosamine. (That according to my daughter who is a vet nurse.) I agree on keeping his nails trimmed. It will help with traction.
As for the leg/hip problems, Murphy has that, too. His hips were pretty bad, but we put him on food and treats with glucosamine and chondroitin in them. It's helped a lot. He moves a lot easier these days. He still has problems, but they are not as bad as before. Make sure he gets plenty of Omega-3's also. It seems that helps with the effectiveness of the glucosamine. (That according to my daughter who is a vet nurse.) I agree on keeping his nails trimmed. It will help with traction.