But, at minimum, you will at least be able to get it on her credit report, which will be at least a consequence, and it will be a warning to the next landlord not to take her.  

We don't get any warning about the lawn.

If they were howling at the moon at their last residence, whether on meds or not, and this resulted in bothering other tenants and getting warnings from management, etc., you don't have to rent to them.You deny based on behavior and ability to pay - not they "type" of disability they have.  

If you become aware someone is sleeping in a non-legal bedroom, issue a written warning and have them sign it agreeing to stop immediately.

They don't warn you of that fact.

Surprise with no warning, when they arrived at their leased home with their moving truck the owner said, "Oh, sorry, the place just sold this very minute and I didn't have time to even call you.  

I didn't monitor any of my tenants until/if I got a complaint from another tenant or I just happened to observe or hear some behavior that I needed to give them a warning about.So, in my case, since I lived in the same building, if they were throwing a loud party, I'd usually see or hear it.  

Would you advise any "warning" or "heads-up" before the closing date?  

I verbally warned them about the swing, and also had them get basic renters insurance (it is in the lease). 

If your lease says they can't cause problems or bother their neighbors you can give them a written warning to knock it off, or they'll be in breach of contract, and if they don't knock it off, you can evict them for breach of contract.Yikes I hate HOAs.