If you are a legal property manager in your state the owner should have the unfettered ability to allow you to act as his/her agent to enforce the lease, whatever provisions they may contain plus whatever your state laws allow.

You and your legal, tax and financial advisors should review this transaction in greater detail, especially the PLRs, to ensure you understand the significant risks involved and are structuring the transaction as close as possible to the PLRs to mitigate some of the risks.

Any legal issues I should be aware of in this situation? 

If you need financial help, ask under the "Finance, Tax, and Legal" forum.

I've seen other people in the forum who simply use independent savings accounts but it is not clear to me if that is legal.

Purchasing the LLC gives you ownership of the property, but it also opens you up to additional legal exposure since the entity has been active, and there is no way to really know for sure what else they used the LLC for.

A buyer agreement is the legal document that provides the agent with the assurance that he/she will get paid if they work with you to complete a real estate transaction. 

If you need financial help, ask under the "Finance, Tax, and Legal" forum.

In Illinois, when an agent does that, there are functions normally expected of the realtor that they are legally prohibited from doing.

If you know of any legal entity in TX that can help in a case where GP is not doing their job (maybe a branch of SEC), please let me know.TIA