well some of them..

so far ive found the Netch leather helm, nordic fur helm and nordic trollbone helm.

always thought they couldnt wear helms at all. Well just thought Id share incase anyone didnt know.

In Morrowind argonians and khajiit can't wear close-faced helms, open-faced helms (like the ones you mention) are fine.

Glass helms are ideal for beast characters.

I concur. Looks awesome.