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.

@Neil CopelandYour LLC does not qualify to sponsor a Solo 401(k). 

@Eric B. 10% is a little extreme, that’s probably atypical but in this case the rent was $2,000/mo, there were over 30 qualified applicants that applied, and rents had gone up 10% in the area the previous year, so the big increase was a function of supply and demand.