Also, we require a 620+ minimum credit score for all applicants, and anyone 18+ must apply.

I've recently started building a software application that allows for behind the meter aggregation for both electrical and gas utilities.

One thing you might want to consider is partnering with microsoft and adding a third party app to their office 365 suite of products as they have an accounting arm and many other applications already in play that you could add on just for property management and it would work on their system to integrate everything.

I am currently receiving 5 calls a day for applications.

For example, an experienced general contractor who does significant remodels of nicer homes might choose to go into house flipping because their practical experience is directly applicable.

Youll need to read through them and put in an application for an ADU license 

@Gabriel Dent Depending on your work and savings, it could be worth doing an application with a lender to see what you could get preapproved up to so you know what range you can offer within and then compare those duplexes, triplexes, and fourplexes to where you could rent for the time being instead. 

For instance, we tithe using cash and we use prepaid Visa credit cards, we don't take a tax write off for it and no one but me and my wife knows how much or where the money gets given to.

However, every time my contractor submits the applications, the city requests new revisions.

There is a 12 month loan seasoning requirement for a cash out loan, and fha and Va have seasoning requirements for rate and term refinance, but assuming as it is investment property that is not applicable.