Your plan should work, just don't leave them in the garage if they are at risk of freezing. If freezing isn't a problem potting up should be ok, just don't use overly damp potting soil or give them additional water until it warms and they go outside and begin to grow.

Personally I would just wait. I can't think of any advantage (plant-wise) to potting them up early.

Helpful, makes a lot of sense, thanks!