I've spent a lot of time trying to build an all discraft bag, and basically come to something along the lines of what you've got. Personally, I don't see the need for buzzes and comets, but the two discs fly very differently and there is certainly room for both. Also, I've tried every fairway driver that discraft offers (or close to it) and there really isn't a decent one that covers all the shots. Avengers are nice, but they're pretty overstable and unless you have a really beat one, you'll have a tough time covering every shot you need with them. I second adding XLs for something a little less overstable.
I think the Avenger is a little more overstable than a teebird, close to an eagle, but, in my experience, they have more LSS, so it is more difficult to get them on a line similar to straight.