I think Stampede will still be on around July 8 so make sure you have your YYC accommodation sorted out soon.

I agree that the itinerary is ambitious but it's not unrealistic. Banff / Jasper in particular are beautiful places so do plan on slowing down to take it all in.

Enjoy the seafood in YVR.

For Niagara Falls, you can check out this link to get a few ideas on wineries. One of my favourites is Le Clos Jordanne which is owned by Jackson Triggs. I rather enjoy the restaurant at Peller Estates but there are certainly many others to choose from. If you want to really enjoy wine country, consider a hotel in Niagara Falls or a B&B in Niagara-on-the-Lake. You'll have the time to take it all in, perhaps rent a bike and ride the Niagara Parkway / wine country, and see the Falls lit up at night.