Check to see if WestJet is running direct flights for your times. They don't always run them, but it's much nicer than having to stop in Toronto (or Denver, or Dallas, or Atlanta... I've done all 4!) on the way down. As far as I know, no one else offers direct flights from Calgary.
If you are really pressed for time, you can probably skip a few attractions that are similar to their counterparts in Anaheim. Can go in to details if you'd like, but if you do go for 10 days in Jan/Feb you shouldn't have to miss much.
Having never been to WDW before, don't make the mistake of thinking they are similar! The size of WDW is so much bigger than
Disneyland Resort, there's really no comparison. I'd take 10 days and spend them all at Disney World, you won't run out of things to do or see. If you don't mind taking and waiting for busses, you don't even need to rent a car.
Staying on-site is definately the way to go, good to hear you're planning to do that. It's been my experience that you are better off booking things yourself than trying to book a package in Calgary. I've always been able to get significant on-site hotel savings by doing some research on mousesavers.com and these boards. Often it involves buying an annual pass, but the savings are usually well over $500, and that's just for me and my wife! If you want to avoid most of the hassle and research you can book with an online Disney vacation specialist (if I remember correctly, madonna31 on this board is one), or a company like
Dreams Unlimited travel that will find you discounts and make reservations at no cost to you (Disney pays them a comission).