Changer said:

You can hypnotize the other costumes; when she's in any costume other than 'slave' if you decide to make her mindless you get a scene where you adjust her mind from her current personality back into mindlessness.

If you mean you would have liked her to be mindless while also in another costume, I'll have that available when I get the tailor shop open. Each costume is going to be a default for that personality change, while at the tailor though you can pick a costume that over-rides the personality change costumes. So, you could make her one personality, while keeping the costume of another personality.