Depreciate 75% of the building value (excluding land) over 27.5 years for significant tax savings.

When I return to the country after my Au Pair contract ends, I hope to live in the property as my primary residence and house-hack as well.I understand that investing remotely makes things more challenging, but I am also ready to be uncomfortable and challenge myself in this journey as I know it is 100% possible.

You can also look into building a rental portfolio which is a little less hands off compared to flipping.

Again, this is a conversation to have with your accountant to ensure the benefits would outweigh the costs.Another misconception is that there is little value in a cost segregation study for properties that do not have a lot of personal property in them or very little interior build out, such as industrial warehouses.

My wife and I are looking into building a duplex on it.since I am still learning on investing in real estate.

Along with your list, consider building a local team in each market to make managing your STR easier.

I have read I will need to use a third party service to make this happen.  

I also have a $175,000 line of credit ready if something catastrophic happens.

I think it would be better just to stay on good terms and let him know you will contact him when you are ready to sell.

You'll find the most success in a place you are familiar with and where you can build a solid team.