How many of these units would be required to be life impacting in a positive way?

However, the time it was rented (known as "non-qualified use") can impact the amount of gain you can exclude.

Here's an article with some examples: https://finance.yahoo.com/personal-finance/one-extra-mortgag...You can also search for "early mortgage payoff calculator" and enter your own numbers to see how extra payments impact your mortgage.

When the unit is vacant is an ideal time to address issues because its easy to work on and isn't impacting a tenant.

For one, your debt to income ratio will be impacted negatively because this loan will still show up as an expense on your credit report, affecting your ability to get another loan.

What's being ignored is that when a sponsor has a property or properties that are foreclosed on, it can have an impact on their remaining portfolio even if those properties remain solvent.

And it also then showed the average revenue impact of each amenity.

Raising rents even $10 per unit has a large impact on the analysis. 

You may want to request the construction drawings / plans for the utilities that were installed to help better understand their impact to your property. 

Your FICO will not only impact your rate but also the max LTV that will be available to you.