Solutions 2 through 9 are variations of the "pretend God is an idiot" theme and I'll just skip.

There is a bit of trial and error to see what the market will yield. 

This unfortunately is all trial and error and it’s subjective to the judge.  

Besides, at this point you can claim you're heavily medicated and your mind is not so clear.Bid the old tenants goodbye from your deathbed, if they create trouble leaving ask them piteously over the phone, your voice quavering, how they could possibly treat a man so near his end with such callousness and could they please make extra sure they take away ALL their crap and you'll put in a good word for them with the Maker upstairs.Once the old tenants are safely gone, you'll experience a miraculous remission thanks to a new drug trial you just got on in time and explain to your new tenants in the 3 br that all is peachy for the long haul as you show potential new tenants the 2br.

Zip would be best, in my city there's a great variation by neighborhood.

A Real Estate agent told me that we could try it for a while then sell in three years and not have to pay the higher capital gains, so that might be a nice trial but still I worry.

My experience has been that Airbnb has flipped the script in results vs VRBO in the past 3 years (when Expedia took over) As @John Underwood will attest their are regional variations to platform performance.

You have to account for the seasonal variations for these properties. 

It can work but many investors experience trial and error.C class varies by market...from quiet, long-term residents in one market (or location) to high turnover, high touch residents in a different market (or location). 

If he is indeed interested, have him on for a trial period and treat him like you would anyone else in the business and not like your brother.