If it were me, I'd limit shooting to the same cameras.
The T2i uses SDHC, and the HV40s are HDV...
Just for clarity's sake, the former is a storage medium, the latter is a video format. Not really comparable
I had planned on filming in 60i.
As far as I'm aware, the T2i does not shoot in any interlaced mode. Both 1080 (30p, 25p, 24p) and 720 (50p, 60p) HD modes are progressive. I think the HV40 has both 30p and 24p progressive modes--actually native modes, unlike earlier incarnations like the HV20 and HV30. However, it's just 1080, so unless you're going to downrez it to match the T2i 720p, or uprez the T2i's 720p to 1080 to match the HV40, you're probably better off starting in 1080p with both cameras. Just pick the frame rate you like (well, probably the client likes), and use a matching sequence.
The HV40 is 1440x1080 with a par of 1.33. IMO it is best to keep it interlaced.
One can drop the hv40 footage into a 1920x1080 non anamorphic sequence without a problem.