1

Having been to as an adult (and grown up around as a youth) I would spend more time in the Banff, Lake Louise, and Jasper area than in the Okanagan Valley area. Others will disagree, however.

2

It would make a lot of sense to get to Jasper from the west (i.e. Kamloops or Barriere) but that would mean going north from Kelowna which takes you away from Revelstoke and Yoho. On the other hand you could do an out-and-back from Banff to see those two.
Study maps carefully because a lot of roads in eastern BC don't connect in ways you might expect and sometimes a "non-connection" means a ferry.

3

A visit to the Okanogan is about the scenery and the wineries. So really a couple of days is adequate. Really there is nothing much to see/do in Kelowna that is worth 2 days out of your 14. I might be tempted to just stay 2 nights in Osoyoos, see some wineries, take a swim in the lake (one of two that dispute the claim for the warmest lake in Canada) and then head east on Highway 3 rather than north on 97. Then north on 93 to Kootenay National Park where you can choose to go to Jasper or Banff.

An alternative would be to take Hwy. 3 to 3A and go north before cutting across east to Kimberley and on to Hwy. 93. Tip: This route lets you stay in Kimberley which is a ski town with some nice hotels. In the summer their rates are very low compared to ski season rates.

4

Ha ha, Tickleberry's ice cream hardnose. When I lived in Oliver we used to go there. They give locals a 'Frequent Licker' card. Get it stamped 10 times and your next cone is free.