However, I would recommend going with an accountant.There are many qualified accountant's/CPA's on this forum who may be well suited for you.

Qualify a Market: Job growth – at least 2 yrs. going upStable Job Market Net positive MigrationJob diversity – a lot of employers in different industrieshttps://www.neighborhoodscout.com/ http://www.city-data.com/https://www.wikipedia.org/ https://datausa.io/ - DataUSA put together by Deloitte, Datawheel, and Cesar Hidalgo, Professor at the MIT Media Lab – like BestPlaces.net but better.

An experienced agent can tell you if the house will qualify for a VA loan. 

I’ve also used Facebook and Kijiji but seem to get the most qualified tenants from RentFaster.

In general, you qualify for the mortgage first.A good buyers' agent (preferrably that owns investment property themselves) can answer your other questions.

Would we qualify for a conventional loan (20% down, standard interest rate), due to the fact that he will live in one of the units as a primary residence?

I discovered today that the house is located within one of HUD's QCT Qualified Census Tracts. 

Unless you are paying some ridiculous 5 figure sum to someone who is going to teach you “everything” (I dont recommend this btw) I would suggest that you evaluate what strengths you have, what skills you can bring to the table and offer those things to someone in your market.

We have excellent credit and have a pretty good idea of what we would qualify for regarding a new mortgage.

Critical thinking skill to make sense of it all might also be a critical survival skill for the future.