Cris, first off, welcome! You've come to the right place, there are a lot of Canadians here with great experience--very helpful to me the first time around (and since then too!). I think Ted is suggesting that you might be better off looking at the different options one at a time, see what the differences are, inclusions and costs and such, rather than looking at the whole range of possibilities at once. It's easy to pick your dates and go, but if you want to be sure to get what suits your family best, and best bang for your buck, it gets more complicated.
I might be tempted to use a TA the first time, if you get a good one. We used CAA the first time, and got a decent rate, but it quickly became clear that I had more up to date and specific knowledge than the TA did (though she was billed as a "Disney specialist"), and I ended up hounding her to follow up on my requests. Not doing that again.
Sounds like you are like most of us here: you want to be an educated traveller, and do the research for yourself. I would recommend Christine at Fairytale Dreams and Destinations (easy to find with google). She's out of somewhere near Toronto, but deals seamlessly with Nova Scotians.
As Disney is all she does, she is absolutely current on what's the best deal. I also liked that at least a little bit of my vacation dollar stayed in Canada.
Dealing with Disney directly is handy too, but you get a different agent every time you call, so there's no sense of who you are and what you are interested in. And I understand they can't "volunteer" info about discounts or deals unless you specifically ask. And may I just say it annoys the heck out of me to pay a toll call to talk to them.
Once you have a package reservation number, you can do a lot of stuff on line. Disney will give you the number, as will Christine, but I had to wrestle it out of CAA because I think they didn't trust me with it!
You do probably want to do your dining reservations yourself, especially if you get free dining. I'm not sure about paying on line. I know when I worked with Christine she took my credit card number and applied payments when we had agreed that she would, so I never missed a deadline.
If you get the free dining package, I believe you have to buy tickets through Disney, so that answers that question. Otherwise, we use
Undercover Tourist for great prices and great service. You can get an additional discount from the Mousesavers newsletter (will come out again in about 2 weeks if you sign up now...again, a google search will get you there). Mousesavers is a great site for figuring out the deals, if you haven't discovered it yet. The woman who runs it knows the Disney deals, as well as car rentals and tickets and things you don't even know you need!
Hope that helps!