Hey there, to remove paint, just get some paint thinner on ebay or your local hobby shop, the paint should wash right off with qtips. "Mr color thinner" is what I like, but make sure the room ventilation is good, and a gas mask is recommended. You might have to do it a few times to get the paint completely removed. For adding hair, it can be very messy and frustrating at first, you just have to be extremely patient, no short cuts, one strand at a time. You get the hang of it over time. Dab your finger tips on a piece of wet paper towel will help to handle the hair from getting everywhere.
I hope this helps a bit.
Thank you very much for your advice!
As for the application of the hair, someone else told me to use PVA glue and to apply in clusters.
His modified Joker Is actually quite nice, so I'm a bit confused as to which approach is better...