Reservations are a must for Yellowstone-or most anywhere close.
I'm not familiar with the visitors center near Jasper. last July, the town was PACKED!! We stayed at a very nice Provincial "overload area," which was about 10 miles from Jasper.
The Columbia Icefields parking lot might be a place to park for the night (if they allow it), but most of the lot is sloped for run off. There are two Provincial Parks at Jasper--get reserved NOW. Same with Banff or Lake Louise.
Note, we went North May 15th 2017 and traffic was nill---Came back through Jasper and that area on July 4th, and I can't tell you how many thousand visitors were on the road. Around Banff, the Park had folks parking a few miles away and used shuttles on the freeway to get the people about.
Your itinerary sounds very busy, but doable.
