Being out of state, I would suggest vetting your "team", meaning find an investor realtor, lender/s (hard $ / long term), property manager, contractors, etc.

Seeing out there if anyone has any reading lists or content suggestions for sales or negotiation in Real Estate.

Anyone have any suggestion for me?

The 1% rule is a simple rule which is easy to calculate and describe. 

Keep it simple, paint and carpet, buy a good house in a quality area.

The only thing I'd suggest is to raise your rents unless you think you're at the top of the market.

All calculations suggest great investment for 4 bed 3 bath in good school zone, however once the tax estimator goes from $2200 to $9500 due to lose of tax credit from not being a primary residence it hard to see how to get property in SC.

I would suggest either talking with a local bank/credit union about refinancing your existing portfolio and/or one that shows they do MHP loans on their website.

Isn't it like you're suggesting somebody to do something (investing in Costa Rica instead of the US) while you (the experienced investor in Costa Rica) does the exact opposite with your own money?

Since you’re committed to staying close to family, I’d suggest focusing on properties that might need a little work but have potential for appreciation in your market.