My older Lab was not really happy about a crazy young puppy, but she's adapted (after putting Miss Ruby firmly in her place a time or two).
I'm crossing my fingers that there won't be too many "teaching sessions" with the puppy. He's really good with other dogs, rarely goes alpha dog and then usually just showing some teeth is enough. He'll nip if necessary, but he's always been fairly gentle and age has mellowed him even more. I hope all goes well. I was surprised how much he misses his best friend and am hoping having another dog around helps him. And me, too. I miss that dog every day.