I believe food makes a huge difference. Mine has been on raw since I got here at just a couple months old. Everybody keeps complaining about this shedding thing with GSDs? I would find a small amount of hair here and there, but not anything I would complain about. I have a sheet that I use to cover my bed. I wash it a couple times a week. No real problems.
Then Shasta had her first heat. She blew her coat and that was a MESS!!!! I figured, okay, this is what everybody was talking about! Dang! I thought I got a non shedder!
A month later, back to normal. A little hair here and there. I brush her daily of course, but she doesn't even fill the brush with hair. I attribute it to the food.
As for adding a pup, I would say no way I would even consider it! They take so much time and energy to raise them right. I don't think on the road would be fair to the pup, you, or the other 2 dogs. My 2 cents.