Doff store is run by a Caitian in Starfleet Academy. Go into the main Academy entrance, hang a right and go into the office-looking room. Look to the right when you go in; there's likely to be a pile of other captains in there buying doffs from him/her.
Quark, ah yes. The ONE place I forgot to try. I scowered ALL over ESD for Panthro and couldn't find him. I'll hit up SFA when I get home from work.
I was home sick yesterday and the cold meds knocked me out for most of the evening. So when I woke up at 3 AM, feeling well enough to leave for work by 7, I went and puttered around with Season 5 for a while. I didn't feel like respeccing any of my toons for space combat, so I just poked around ESD and SFA.
I showed my wife the doff system when she woke up (she's got a toon on my account), and she said it looks like Space Pokemon. I can't say I disagree with her.