Alabama law can be a bit draconian about deposits but there are strict provisions to follow.Alabama is a one party consent state as to recording telephone calls. 

All notices, demands and/or consents provided for in this Agreement shall be in writing and shall be delivered to the parties hereto by hand or by United States Mail with postage pre-paid.

The lender is not a principal in short sale and is powerless to sell the property without the owners signature/consent.

Accounts can be frozen and siezed under several events effecting your tenant and done so without your consent or knowledge.

Or does the mother not have "legal cause" to occupy the property (addressed in lease: Only those persons whose names appear on the lease may occupy your apartment without our prior written consent except guests for no more than 7 consecutive or 14 total days.), so could I just have her arrested for trespassing?

The other methods such as asking the tenant for a rent increase or asking them leave to let you carry out renovation in the apartment may work but it will be a laborious task especially if they want to exercise their right and if it fails i mean if the tenant didn't agree or consent to your rent increase offer or renovation plan, it will ruin your chances of exercising your right as the owner of the property to use owner occupancy. 

NO PETS SHALL BE ALLOWED, EVEN TEMPORARILY, ANYWHERE ON THE LEASEDPREMISES, WITHOUT THE PRIOR WRITTEN CONSENT OF LESSORS.

You shouldn't have an issue assigning the contract, it would be better to have consent of the seller to assign but you don't need to indicate the higher price.

A tax deed/lien is an involuntary lien - the government places the lien without consent and where a mortgage/dot is voluntary - the borrower gave the lien to a lender.That's the nuts and bolts.

You can also put in the lease if a guest stays over 15 days without the written consent of the landlord, the tenant is in breach of the lease.