For what it's worth, the Soul of Chogokin SPEC line of Evangelion figures have removeable armour (though the beasties are wearing bodygloves, sorry Reichu) if you want a poseable reference of a naked Eva. Unfortunately they're long OOP and very expensive on the aftermarket, and if you want the full set you'll need to take out a small mortgage. Also be sure to pick up XS-01R rather than XS-01, as the original Unit 01 (XS-01) had breakage issues that XS-01R fixed.

Doujinshi is mainly fapping material/fan fiction so l don't think too much about it honestly