Definitely with the rest on the 7D. The 5DMII is useable as a sports camera, and performs wonderfully in low light, but compared to something like the 7D (or even my 40D), there's noticable shutter lag, the limited fps hurts, and as others have stated, the autofocus is going to be quicker and more accurate with the 7D.
I also agree with Samsen (partially) on taking both bodies. Personally, though, I'd put the 50mm lens on the 5D and the 70-200 on the 7D. Most of your shots will be with the 70-200, so you'll want that on your primary body (the crop sensor will also give you a little more reach). You'll also want the versatility of the zoom. When I shoot sports, the longest lens is always on my 40D (generally a 300 or 70-200) and the 5DMII gets the wider angle (usually a 24-70 or 70-200). In your case, the 50mm will work well for shots under the basket (if you'll have access to that location), close in shots (assuming you're going to be near the sideline), or if anything else arises that calls for something wider angle.