BUT I have also heard that it could trigger a due on sales clause, bringing the note fully due at any moment.

The boot amount is taxed as capital gains and may also trigger depreciation recapture.For example, if you sell a property for $500,000 with a $300,000 basis, resulting in $200,000 of gain, but reinvest only $400,000, the remaining $100,000 is taxable.

But we don't know how it works for the tax implications of that for the hairs...Or would a trust be better? 

There are often automated flags that will be triggered if you do it, so it's best just to know how they will react.

Selling would likely trigger capital gains taxes (unless you lived in the property for two out of the last five years or use a 1031 exchange).

So when we did not receive any response to our emails for several days, this naturally triggers concerns and emotions.

Just make sure you guys are comfortable with the area before pulling the trigger.

We want to pull the trigger and start investing in Japan.

We're exploring creative ways to provide him with the cash needed for the down payment while avoiding triggering a taxable event.One strategy we're considering is purchasing his future primary residence ourselves, making the mortgage payments, and then, once we've built enough equity—comparable to the appraised value of his rental properties—transferring the title to him as a form of exchange.What are your thoughts on this approach?

Dig into reverse mortgages before pulling the trigger on anything, specifically HECM's (FHA product).