The-Technique
Smash Ace
As we all know, Diddy is easily one of Robin's worst matchups, if not the worst, so it might help a bit to lab some of Robin's options when she manages to catch his banana.
Robin can in fact copy Mega Man's schtick of footstool > Z drop banana > ???, but unlike Mega Man she can only land a standing grab and jab off of it (that I've tested). At least she has a confirm into Checkmate off of this tactic.
Glide toss > F-smash is also guaranteed. There's also glide toss > grab if the opponent shields the banana, although I haven't been able to test that yet.
Robin can in fact copy Mega Man's schtick of footstool > Z drop banana > ???, but unlike Mega Man she can only land a standing grab and jab off of it (that I've tested). At least she has a confirm into Checkmate off of this tactic.
Glide toss > F-smash is also guaranteed. There's also glide toss > grab if the opponent shields the banana, although I haven't been able to test that yet.