Well, water under the bridge about that daughter (w/ a 6 mo old son) who has been living with you for eight months.
The management/LL will not allow anyone to live out the security once you are gone. Security is to offset damage and repairs that are beyond normal wear and tear, and not for rent.
I'm guessing the 28 yr old w/the 6 mo old son doesn't have a job.
Her options are: 1. She may go to a homeless shelter or women's shelter with her baby IF you can get her to move out.
2. She may go to her local church and see what they have in place for the homeless (ummmm, if she is not a member of the parish she's likely to be S.O.L.) or if they can refer her to a religious organization that could help.
3. She may go to a social services agency (welfare offices etc) & say she is homeless and see what they come up with as temporary housing.
4. She may move in with a friend.
5. She may show up on the baby-daddy doorstop and just plant herself there with his son.
6. If she has a vehicle, she may temporarily live in her car with her son.
7. Go to the local YMCA or YWCA or Goodwill or Salvation Army offices and see what they might suggest.