I've always used my business solely to generate an income/paycheck, however I'm ready to transition and use my experience to facilitate investment opportunities.

It sounds like an exciting time for you transitioning out of the military and into real estate.

We are transitioning into the US Market, and looking to partner with established and experienced developers. 

I aim to begin with Fix & Flips to create immediate cash flow and then transition to STR/MTRs.

I think that is another viable option, especially if more accessible public transit becomes available. 

I would suggest trying to find something that is 10% or better UNLESS you have another reason to buy it, like high equity or high reward in the future (transitioning area that will see high returns in the near future).2.

I started out 20+ years ago appraising then transitioned to investing.

lower the size of your unit and therefore your build cost per unit, your sale price will go down but focus on density and get familiar with zoning and what your city will approve. my best suggestion is to do it in downtown districts where there is unlimited height and unlimited floor area and you can build every square inch of the property and reduce parking because of proximity to transit. property values are higher, rents are higher in downtown markets, there are just too many economies of scale compared to suburban deals.

We are transitioning into the US Market particularly Texas.

I'm transitioning into real estate & started a couple of other companies.