Can you send a girl to Meta Bordello if they're already in the cell?
Depends on the girl. Essentially, it almost always has to be a heroine that you captured with a mind control device, and then upgraded the device to Level 6, then Unlocked, then reset the device. Which costs just shy of $1,000,000 to do, not counting the cost of the device itself.
So, usually, girls that are "Unlocked' you'll only reset their devices if you've become bored with them, or are trying to 'unlock' some special scene or Villain, say Lobo who you can't hire (unless you cheat) until he's had sexy fun time in the Bordello with Hawkgirl, Supergirl, and Wonder Woman.
I've noted that, at least in my playthroughs, that Starfire is the exception to this. I've been able to put her to work and still interact with her in her cell after unlocking her device, which actually sort of fits with her dialogue, i.e. she used to be a sex slave. Well, technically she still is a sex slave under Lex, but he's a lot nicer to her than her other masters...
That may be a glitch, but a noteworthy and fun one nonetheless.
Also, note that a number of girls don't have Bordello scenes. You can still assign them to the Meta Bordello if their control devices are at level 4-6, but they may not have scenes for the Bordello, Private Room, and/or Exhibitions depending on if the art for those scenes has been created yet or not.
As for Villainesses, usually you can only assign them to guard duty at the Meta Bordello. In at least one case, this will trigger extra scenes if certain heroines are also working at the Meta Bordello...
So far, I haven't seen any leash scenes for the Meta Bordello, but those could be fun if they were a thing at some point...
Also, although not related to your question, I think that leash scenes at the Glamour Slam or the Street scenes should rake in a little extra cash. My logic on the street scene is that Lex has a cameraman hidden somewhere that is filming and the is uploading the street footage to porn sites, hence raking in a little more cash, Not a huge amount, but this could be an ongoing small income stream. As far as I can tell though, this doesn't happen, it's just a thought on my end, to justify 'cheating' on the cash to speed play-throughs up a bit...
