I have had some of the issues bringing new pups into my house. I have a Laso --not the sweetest temperament!! He used to play and run around and for a long time he wouldn't. It was sad. I also give him "alpha dog treatment" --but his little brother is twice his size and kind of goofy and knocks him around when they go after toys but respects the "pecking order" when it comes to treats, feeding and walking. Then we brought the yorkie home. She thinks she is the alpha dog and life has been interesting
The good news is.... they now sleep together, play and eat together. Sometimes Sammy "does the lip - teeth" snarl at Remy but it is all good.
I make sure I give Sammy lots of hugs and attention and I guess overtime it worked.
hope that helps