I'm sorry. I was unclear.
Are those names you listed with '-a' suffixes gender neutral? For instance I know Boricua is. Are Nica, Paisa, Carioca?
Further, am I right to assume that Chapín & Gachupín are made feminine by simply adding an 'a'? If not, then how?
And seriously, thanks again. You've answered a whole bunch of questions in just two posts.