First suggestion: add a ref pic! I had to Google the name and I hope I was looking at the right person.
If I have to do face + body paint, I usually go for Ben Nye magicake and PAX (respectively) -- though of course there's a thousand other things people like.
As for the body paint though, PAX is really the way to go if you have to use a lot and it's going to be on parts of your body that are inevitably going to even bump into someone so you don't get paint on his or her costume. (If I was looking at the right picture upon Googling the name, then it will be on body parts that will inevitably bump into someone/brush on your costume.) It doesn't come off on people when powdered -- it doesn't come off at all, unless you really
take it off. Read some more about it here --> http://www.cosplay.com/showthread.php?t=216634
As I mentioned, I like Ben Nye magicake for the face (which I apply with a sponge), but I've heard good things about other brands as well, like Snazaroo and Mehron Paradise. (You can't put PAX on your face, and you don't want to.)
As for sealant, I use the Mehron translucent powder with antiperspirant (as I find it's less visible than Ben Nye, but other people have different preferences), and then I use the Ben Nye final seal spray over the top, just for a little extra backup.
I personally think that fluorescent body paint would be a nice touch, unless you know the chances of you being in the dark are really low -- then it would still be a nice touch, but you might want to make it a last-touch type thing. Buy everything else you need, and then if you've got extra money, buy the fluorescent paint. Unfortunately, I can't really recommend you any brands of fluorescent paint, but someone else here probably can.
Good luck with your costume!