What places must I visit when going to Kissimmee/Orlando, Florida?

You should definitely go to Walt Disney World, at the very least just to spend a day in the Magic Kingdom! I think you'll regret going back to Canada and saying you were right there in Kissimmee without going to Disney! In terms of shopping, I think the places you listed all seem like pretty good deals, but may not be things that you don't have in Canada. CVS and Walgreens are drug stores, not clothing stores, just so you know. I would also recommend Old Navy!