What are your required notifications in California? I know there is a federal lead paint brochure that we give out, warning of the possibility of lead. We have not had any of our places tested. As far as asbestos, we have not been asked., nor have we tested. Given the age of the homes, it is probably there, but we have not disturbed it.
I think your best bet is to find a way to end the lease with this person. If she can't stop thinking about the ceiling, then she will not be happy there. I would never allow a tenant to do work on an apartment, including testing of any kind. It says this (the work part) in my lease. This might be one of those situations where both sides lose a little bit, but you give her back her deposit and last month's rent and she moves out immediately.
You can't convince someone like this...we had a similar situation with someone that brought in bedbugs on a piece of furniture, then insisted on fumigation, then said they couldn't bear to live in an apartment that had been fumigated. Grumbling to ourselves, we let her out of the lease and lost a month's rent. she agreed to use security deposit to pay for the pest control. So happy to have ended it there...well there was the parting gift of a sewer clog on the way out, but yeah...the relationship ended.