Have you considered the idea of house hacking as an option?

Other than Regus there are very few options. 

Most cost effective option I have found.Guest breaks a refillable container, no problem , $5 or less to repair.

Check county recordsUse online search tools like PropStream, Reonomy, PropertyShark, etc.Use local GIS mapping tools (ask your county)Search online directories for LLC or TrustTalk to neighborsHire a skip tracerSend a letter to the propertyThere are a lot of options.

The most knowledgable people on market rents are the prospective renters who are currently shopping around trying to find the best option for themselves to live.

You can do a trial and see if bank feeds connect, if it does, I would then recommend using it over QBO.One of my client that just started in development is short on funds so Xero was the only best option and they are using a local bank so we couldn't connect and a lot of manual entries. 

I used to do contractor work and we would always inform the customer of their options.

That would be best option as a traditional bank wouldn’t do this I read that I can assume the existing mortgage.

I would first check to see if HELOC is even an option - in TX its hard to find and can only be done for a primary residence.

Exhaust all of your conventional or government financing options before you get into DSCR.