If Wario actually matched up well against Rosalina, I would've expected Abadango to switch to him during Apex instead of being timed out repeatedly as Pac. Wario hates range and disjoints, and RosaLuma have both aplenty.
Re: Zelda, the reasoning is that Din's/Phantom/DA all dispatch of Luma easily, her dair is great at intercepting Launch Star (active 11 frames, even the weak hit spikes) while Farore's Wind is harder to edgeguard against, and Zelda kills much earlier than Luma-less Rosalina. I don't agree with the ratio (Rosalina wins imo) but w/e, point is she has tools in the MU.
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Mega Man and Mario match up the best out of the characters you currently play. If you're strictly looking for the anti-Rosalina, pick up Diddy. Above all else however, I'd suggest that you play Rosalina yourself for a bit to get a better understanding of her weaknesses and maybe convert to the superior character.