IIRC, Rogue's ability is meant to work on humans or near-human species. This includes Marvel mutants and a few alien races, but I think Kirby would be sufficiently different that she wouldn't be able to copy his abilities.
That said, there's no guarantee that Kirby will gain any abilities from Rogue. Loads of Kirby enemies don't give him any abilities, and in Smash for example, copying Dedede for example effectively does nothing for them.
Love and tolerate.