He has a significantly lower AGI than my wife and I, would it benefit us for him to charge me for lawn care?

The realtor commission is nothing compared to the additional benefits and sales price. 

(About 25% increase in 2 years) At about this month next year, I will be moving to my next duty station (don't know where to yet), and was thinking of refinancing my VA loan to a conventional since I will have over 20% equity to avoid PMI and to free up my VA benefits to use where ever I'll be stationed next. 

However, I have a fairly unique business skill set that I'd like to apply to the real estate "game" that will provide a ton of benefit to others who do wholesaling.

So, until you gain more experience/transactions (licensed or not) you may not be doing yourself justice by representing yourself.Otherwise, yes if you can afford the ~$2k to maybe $3k in annual dues and fees, there can be a benefit to it. 

You have to do your own cost and benefit analysis but I am usually in favor of selling the condo because duplex or SFH appreciates better and you don't have to deal with rising the cost of HOA.

There's benefits and drawbacks to every loan- the drawback for FHA is the PMI (which you can refinance into a conventional loan and eventually have removed) but the benefit is that you can keep more cash in your pocket and expand your portfolio quicker. 

Then force appreciation through repairs/upgrades/ADU and reap the benefits of CA's high RE appreciation.

Meaning don’t buy something just because you like it--buy it on favorable numbers.If you are looking for a fixer for instance, it's intelligent to find a fixer where you believe rehabbing will allow you to increase rents, and it's best in an area with increasing employment--as well as many other things.If you want to approach this in a hard nosed manner (not everyone does) it's smart to make all of your buy and sell decisions based on financial measures, such as the income stream, and on the return on investment that the income stream represents--as well as many others.It's also intelligent to calculate:1.Its Projected Cash Flow2.Its Projected Appreciation3.The Loan Pay down benefit you will get from owning it.4.The Tax Shelter you will get from owning it.As well as many other things.

If its a benefit to you and your tenants great keep it.