Start with whatever your son's natural talents and inclinations lean toward.

Due to amortization schedules front loading; you could be burning money if you go light on your down payment and use a 30 year. 

Naturally my DTI is high, however my only debt is our primary residence mortgage I have had since 2020.

In these early stages of learning and developing as an investor, I'm primarily focused on properties that may require the following: paint, flooring, bathroom/kitchen remodel, drywall, light fixtures, exterior landscaping, siding, or new HVAC.

Due to the nature of the STR property criteria in Cape Coral, it's very rare that a STR could be converted to a successful LTR.

I'm also confused by the nature of your charity.

Wait...it's not natural for an animal to wear a collar, but it's natural to spray the yard with a pesticide?

With fresh paint throughout inside and out, brand-new roof, dual HVAC systems, updated water heater, stainless steel appliances, lighting fixtures, outlets, countertops, and PEX plumbing just to name a few.

And natural wood interior walls for that cabin feel.. can you post a link to what you recommend a  cabin should look like I am just curious . 

So you will naturally see more of those higher-priced homes in those markets.