I think you're onto something. Although, once I got the option I started using the more NPC-like mercenaries (skorpikis, lizardman).
sure! dude mercs, lady mercs, cookie mercs, gargoyle mercs, arcworker mercs, ghost mercs! all the genders! there's even drakkin mercs if you want to be somewhere in the middle!
For me it's TRUE. I'm a female and I have Male mercs. Only one expectation is the Jann mercs. I just keep what they got the first time buying them. My main and my favorite characters have the DE pirate mercs....because....well.... I like their tight leather pants haha
I have both male and female dark elf mercs. I didn't look at the gender when I recruited them but they were the closest ones I found to the entrance to the guild lobby.