2. Can i color the eyepiece with tamiya clear red and outline it with a black 0.1 tech pen and cover it with tamiya clear? ( i'm working on a MG Strike with IWSP)
That should work, but aren't the eyes green? If they are, I know Tamiya also makes a clear green. Generally--and this is just my opinion
--the clear colors don't show up well enough unless you have something behind them (like the face behind this Luna Pawn visor
). You may want to consider using a solid (non-clear) red (or green) instead. And your tech pen might have too broad a point to do a good job with the outline. Be prepared to wipe away excess ink from the eyes with a cotton swab or something similar.
In the end, try what you think will work, but be ready to adjust it based on how it actually turns out.