I live in NC, I'm 41, my wife is a high W2 earner, and we don't plan on touching this money for 12-15 years. 

Very user-friendly.Buildium: Comprehensive property management features, solid financial tracking, and an excellent real-time dashboard.Propertyware: Extensive reporting capabilities with historical P&L, cash flow, and return on equity metrics.AppFolio: Detailed financial insights and an intuitive dashboard that keeps everything up to date.Checking out their demos will help you find the best fit!!

Do you plan to refinance after adding the value?

My plan would be to stay with family in CA the 2-3 months I am back from work in the U.S. , and have the property 100% rented out for the year.

(Assuming your project fits the criteria for such state funding). 

Many beginners jump in without a plan leading to mismatched goals and markets.

Here are some of my next recommendations based on your current BP Profile Bio:- Listen to the BP Real Estate Rookie Podcast (https://www.biggerpockets.com/podcasts/real-estate-rookie) - Read "Set For Life" by @Scott TrenchI see that you are about to graduate college and plan to become an Army Officer by May 2025!

Try out the BRRRR (Buy, Rehab, Rent, Refinance) plan to grow your list of homes fast.

My plan was to build and sell the beach house or have it on AirBnB. 

It's a great plan.