I had TF2 on the brain the other day while playing some SSB4 & an Idea for a Mod dawned on me: How about Medic over Robin.
So here's my ideas: Firstly, Since this would be going over just Male Robin, only three alternate costumes are necessary only one of which is actually based on anything, that being the Blue (Blu Team) costume.
Bonesaw over Sword. Ubersaw over Levin Sword. Fancy Spell book over Tomes.
One Idea I had is regarding voice lines, and what lines of Medic's I felt would work well over Robin's. Up Taunt: "Let's tip the scales!" > "Let's go practice Medicine." (From Meet the Medic.) Side Taunt: "Prepare Yourself!" > "Gesundheit!" Down Taunt: "You're not ready." > "I promise I will heal you!" Victory 1: "I'm always three steps ahead!" > "Zhat was Doktor assisted Homicide!" Victory 2: "The key to victory lies within." > "Oops, Zhat was not medicine." Victory 3 (Chrom Victory): "It seems our fates are joined" > "Ve did it Kamerad!" Side Special (Thoron) "Thoron!" > "Auf Wiedersehen!" These are the only voice lines I could really think of replacements for, aside from Robins lines for casting various spells which could be swapped out for Medic's lines for casting various spells during Halloween mode.
So yeah, those are my ideas, if you'd like to give this a try then be my guest, this is another one of those ideas where if I had the ability to make it myself, I probably would, but I sadly don't so I can't.