Step up in basis to reduce your heirs' taxes and morePlus the real estate tax "deferral" can end up being permanent if played correctly

You're not in the position to be a cash buyer...as a former wealth manager, it's simply not a good play for you for many of the reasons stated above and more.  

You need to remember that, hopefully, this is a long-term play for you, so work with a trusted STR designer (I have great recommendations), and spend the money upfront so you can be the most successful in your area.

There are many good locations - I'd suggest that you play around with the "Market Finder" tool at the top of the screen here, included with your pro membership. 

My fiance and I are in a unique situation as I play baseball professionally, and she works online and plans to live with me during my season.

I also think, the flat rate ppl are playing to a race to the bottom. 

Working with a great broker can also help as they will know how best to represent your interests and play the game.

Potential redevelopment or ADU play. 

Umbrella insurance will never come into play for Property damage (fires, storms, floods, etc.)It is liability coverage only.I'm an insurance agent and have seen umbrella claims from fatal car and boat accidents. 

Income-based valuation only comes into to play once you get into commercial property (5 units and up).