For that reason I built a full-functioning cash flow model taking into account hard money, the mortgage refinance and all relevant operating expenses to assess monthly cash flow.

Once you have REPS the distinction between passive income (or losses) and active income (W2) disappears and all those tax losses you have been banking can be applied to the W2.Good luck

This is why it is important to look at the market regularly and maintain an understanding of what prices are doing.When you are actively marketing a home, I recommend looking at the market every day or two.

You should know how you can contest your assessed value, especially if you are buying the property for below current assessment.You should understand if there are any tax abatements available today or in the future.There are real estate tax consultants in basically all major markets, or your real estate agent can likely help with some basic questions, as well.

They are actively participating and easy to reach. 

Now with Covid we do not even travel to the U.S. so will use Facetime to see the progress I also get reports on our internal system for all my our  contruction activities.

Lots of good advice above- I think an active, professional network of pros that know and trust each other is essential.

For water, is it best to hire a plumber to come out, turn on, and assess?

The problem is NOT the use of remote entity as any fraudulent  activity will fall back on the individual performing fraudulent acts.  

(Or a lot if you're dealing with a scam turnkey company, of which, unfortunately, there are a decent number.)BRRRR is much more active, you buy a fixer as you note, oversee the rehab yourself and then either manage yourself or find a manager for.