I know that market backwards and forwards, because I operate there.  

If it's a commercial property the property value is determined by it's Net Operating Income (NOI) and Cap Rate.

They do not operate separately and do not act separately because funds cross back and forth constantly and continually with no formal arrangement. 

That or operate knowing that one day you could get slapped with a cease and desist.

I suppose they want to get more for their buck since the washers are coin-operated.

Having labeled and easy-to-identify shutoff valves is a must.Train tenants to operate the shutoff valves at each of their fixtures (under the sink, behind the toilet, etc).

-I'll be handling all of the books and operations.

A lot of questions here...As your dad has a 50% interest, and a trust owns the other 50% of which you and your two siblings are the sole beneficiaries (I presume), it might be advisable to, after the trust interest is distributed, to have your father, you, and your siblings contribute your interests to an LLC in exchange for shares of the LLC (usually called "units").The property would be re-titled in the name of the LLC and the LLC can use it as collateral for a loan.It's usually highly advisable to engage an attorney to draft an operating agreement in this scenario to get everyone on the same page about ownership interest, who is/are the managing member(s), what happens when someone wants to sell -- do the existing members get 'right of first refusal', what happens if a member passes away, etc.

I am an experienced real estate investor, but had never operated as a loan agent before.

As an agent, this is how I typically operate as well.