That does sound like normal puppy play and it seems like you have a pretty good handle on it. I have a 6 mo old puppy and an older dog. My puppy drives the older one crazy wanting his attention, so I usually intervene by giving a pull toy and encouraging a game of tug…Harry really doesn't have to do much more then sit there with it in his mouth while Sunni acts like a wild woman,haha. She's met her match though. At the moment I have my daughters 60 lb Bulldog, who is just over a year, still very puppyish. Thank God they are both spayed/neutered, haha. Sunni isn't that much bigger then his head, but they are having the time of their lives. Bear seems to really know how to play gently with her..quite sweet. I did have to separate them earlier because the play was escalating and just his sheer size and the force they were starting to go was enough for me to end it. Seems like all it really takes is a little diversion for a few minutes then they are calmed down.
Seems like you are doing all the right things by crating them separately and keeping an eye on them while they are in this crazy puppy stage
Good luck.