Depends on the shots you want to get. Plan those out and then think about format. I don't think rolling shutter would be too much of a problem if you keep the camera fairly steady, properly follow the subject, and have the right focal length.
As far as focusing goes, maybe get a hold of a cinema lens with a longer rotation and a follow focus.
Do some test shots though. Watch hockey games and see what angles they use for replays during broadcasts. See what they use to cover certain aspects and how that incorporates into your piece. You could definitely do it with either camera you have now.
Maybe if you have some specific shots you have questions about that may help a more specific answer. But I would mostly suggest study games and the game and you'll know how to follow what you want how you want. You'll know what to anticipate, etc etc. But, test. Do test shots.
And I haven't used it, but I know FCP X has a rolling shutter fix in it? I don't know how effective it is, but that may help mitigate any issues if you do have them.
The biggest times i see rolling shutter come into play if I'm shooting on a DSLR is if I bumped the camera at some point, something that creates a really quick movement, you'll see the jelliness. But standard following isn't an issue. Hockey's fast, but not that fast.