I plan on putting a white pigment in the epoxy for the inside of mine. From what I've read, it's not a good idea to put the pigment in the epoxy when you lay the 'glass down but will be fine for other coats. Wont have to worry about scratches showing up as much.
No idea on the aliminum but, I'm also planning on mixing carbon for below the waterline for abrasion resistance. Not the best looking stuff but, I plan to keep that side underwater for the most part
Whoever you buy your paint from should also have a primer for it. Make sure the primer will work with the paint. On big boats, I always used a primer between epoxy and paint as a bonding agent (Per manufaturer's reccomendation) I've never seen it lift up or flake.
-David