While I am very knowledgeable about home construction and she is very knowledgeable about real estate sales, neither of us are knowledgeable about the investing side.

Any chance you could share the spread sheet also? 

The key is that in order to completely defer all tax you must purchase at least as much as your net sale. 

But at least you have a chance, and aren't exacerbating the problem as much.

If this is a one-off issue and they generally handle things well, maybe give them a chance to make it right.

Chances are the prices of houses will keep going up, but the interest rate will fluctuate a lot during these 20 years.

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

That is different for everyone, but tailor it to your family's goals.She is in medical sales and dreads aging in this industry, so being able in 10 years to transition into fulltime REI with me is appealing to her.

COVID created a chaotic spike in both the sale & rental markets, attracting even more new real estate investors.

It is a failure to take the chance and see what you are made of.