FIRST has no restrictions on logos (beyond decency and GP, of course). Teams have changed identities before, either mildly (e.g. 2815 not using the
robot chicken (see the corner) this year in favor
of the robot's claw holding the number--though we kept the same name and color pallet) or radically (47 and 65 merging to create the all-new-but-oh-so-classic 51).
If you're trying to think of how to merge the two effectively, you might want to look at how The Business World does it. I enjoy reading
Brand New, which occasionally talks mergers amongst their coverage of new brand identities.