This is my assumption It sounds like you may not trust your realtor and if thats the case I would say just make sure your solving the right problem. 

There are some unincorporated areas with San Antonio addresses that are in adjacent counties. 

Her having financial problems stinks but you aren't a charity (if you are, I'll give you my address).

Our properties are completely renovated, have qualified tenants in place paying top market rents and are professionally managed by one our trusting partners.

For the purposes of this section, a tenant shall be deemed to have relinquished possession of the premises upon any of the following:(1) Execution of an order of possession in favor of the landlord.(2) If the tenant has physically vacated the premises, removal of substantially all personal property and the providing of a forwarding address or written notice stating that the tenant has vacated the premises.

As already implied I would look very hard at the tax code I am sure they address this situation. 

BP forums will address many ideas and strategies  I expect in the next few months. 

You need to build real authentic relationships with the owners, educate yourself and them on the foreclosure process to build trust with them. 

I’m printing off return address labels and am wondering if I can put my title “First Lieutenant (name)” or not.

They can at least give you the address that they mail the tax bill to.