We have done houses and cash for office.

There is a big caveat to that though, which is that (1) I haven't entered into any LPs myself, and (2) the clients I work with are large real estate investors not using conventional bank financing.However, I did make loans to LPs as a bank officer prior to practicing law.

Can you go to the local city office and ask about the invoices?

You will need to contact your local buildings department office for those answers. 

Is Brad someone from an office local to you, though?

These are not allowed due to the zoning and since the property is in proximity to the airport which places density requirements on the parcel.My plan is to move into the house and fix the other building up into office space to rent out. 

I have a few attorneys that our office highly recommend that would love to help you!

@Andrew Mercer its highly unlikely that you will be able to add another unit so before you start anything research with the local code enforcement office to check if there are occupancy permits for the existing 3 units and if a fourth can be added.

I was residential loan officer/mortgage broker from 2000 to 2008 and a Realtor since 1993.  2008 and the next few years were difficult times to be in real estate finance so I jumped to bank owned sales during this time, so I have both perspectives.Both as an LO/mortgage broker and real estate agent I would regularly have banks/lenders ask for a comp-based appraisal and a rental survey on 2-4 units properties; which is Fannie Mae Form 1025/Freddie Mac Form 72. 

I'd run this by your broker to make sure you're not breaking any office rules, but I am also licensed in CO and see no issue with it.