I'll also note that, yes, the tech for expanded costume permissions does exist such as with species specific costume unlocks and the Amazon Borg. But my hunch is that it probably calls for a lot more database digging than is on the calendar right now and still runs afowl of faction permissions and duty/off-duty weirdness.
So I'm gonna continue to venture to say the simplest short term fix is to allow Marauding BOs to wear KDF uniforms for now, pending new tech and more permissions that could expand that into off-duty costumes later when that can be properly scheduled.
I do have the formal wear pack, yes. The plan was to have an Andorian setting up turrets in a cocktail dress and heels, and currently being robbed of whatever it is I expect to get out of such a scene is an absolute shame.