You have guaranteed payments coming through and you can allocate your rehab dollars and buying another property on top of this one.

This is the price you pay for having the low initial down payment unfortunately. :( 

I don't remember when was the last time that I have to go on IRS and/or my local taxation website to file payments personally. 

That means the insurance company cuts you a check equal to your rent for any month the property is uninhabitable (e.g., fire, flood, hurricane).

I'm not sure if there is such a deal structure or even the risks involved if engineered,  but the idea would be that the title doesn't really transfer / and a final balloon payment isn't made until after the property actually transfers to the children.   

I would even obtain a COFI arm permanent loan where the payments were based on an interest rate lower than what the market rates were.

A strategy I try and use is to push closing dates or pull them in to the beginning of the month to give you that extra time up front before the 1st payment is due.

.- Eyeing areas like Worcester, Shrewsbury, Grafton, and Millbury for a single-family house, priced around $500K, with a planned $100K down payment.

Fixed it up, rented another room, refinanced a few times to lower the payments.

**Another aspect is that I am worried about investing my cash (currently in 5% HYSA) into real estate and then the market declines as interest rates are cut.