Why doesn't the Chatter Feed refresh when the model reloads?

Glad it worked out for you Peter.  It would take some testing to truly determine which approach is faster.  On average, I was seeing the template/iframe approach typically resolving faster than page include approach but not every time.  You’re right, saving the model load helps for sure.  Either approach is making a network call but I believe there will be more network calls in the page include approach than the iframe approach since it doesn’t incur the full “skuid page” overhead.  If it were me and performance aside, I’d stick with the iframe simply because it’s less maintenance than the page include approach long term (it’s also a more portable solution for other SObject feeds).