A friend proposed making Redcaps tough enough to decorate themselves with iron body piercings. But the things I want to keep are:
Redcaps wear and wield actual Fae-bane iron without harm (I am open to that being an Aspect one could compel to harm them as well, such as them having to maneuver bizarrely on occasion to keep from self-harm).
Redcaps are Fae creatures (a Goblin court seems as good a home as any).
Redcaps soak their caps in the blood of their prey, and must keep those caps wet with blood or they perish.
I wrote a Redcap character for an upcoming Dresden LARP next weekend, and some of these things are going to become Important.