I would love to buy it, but I’m in still in the education/capital building faze.  

Fighting for a cause:In the military, they instill in you that "you are fighting for a cause bigger than yourself" a phrase used over and over again to assure you that you are fighting the nation's battles to protect our way of life.

If the current owner has a mortgage out on the property how can I get this place locked in still?

Good deal - the good thing is the military has likely instilled a good work ethic and discipline in you - these are key traits to being successful in my opinion. 

It has seen a 1.4% population increase since April of 2020, indicating people are coming back, I might call it a Yellow flag, but nothing to be overly concerned with. 75% of home buyers in Wilimington that living locally, are seeking a home in still in Wilmington which is great data.

The property is zoned R-6 and in the Citizens Guide to Residential Zoning Districts & Regulations on the Richmond City website R-6 properties allow for "One dwelling unit located in an accessory building, containing two or more stories (lawfully existing prior to the date of this section), with conditions" ... which to your point sounds like accessory units are only "grandfathered in" .. still I will reach out to the planning department for more information.

Some of my considerations were training/mentoring, flexibility in time, commission splits, reputation of the brokerage, and goals that brokerages may instill on their agents.  

So far, this isn't working and I'd like to instill house rules.

All kinds of things can come up, what you need to do is instill the motivation to do something.

He may not be here to guide you through the next chapter of your investing career but his infinite wisdom is instilled in you so I'm positive you'll be just as successful as you were before.