The bank valuation should obviously be a useful objective view on the valuation of the property.

My view it’s that it’s always better building a brand rather then focussing purely on the aggregators (whether Airbnb or otherwise) but it would depend on your objectives as an investor/operator of your own spaces. 

I would think that participating in a sub to deal as a principle poses an even higher risk.

Following the shiny object, throwing money at a market you don't know well, and blindly trusting strangers that have a clear profit motive put you in a poor position to succeed regardless of where you choose to invest.

Here is the how I would explain it to a kindergartner:The true power of a 1031 exchange is the ability for an investor to meet their investment objectives without losing equity to taxation.With more money they can buy larger, multiple, or more productive properties.What is the alternative?

You get as much objective information about them so that you can make an informed decision. 2.

This is inflation.Leveraged REI uses this principle by connecting two points in time with a hard asset, and taking advantage of it by paying off an asset that you bought for yesterday's cost with tomorrow's  money - it's like a financial wormhole

Maybe look for a different type of tenant that doesn't leave every year or sell the place if it isn't meeting your other investment objectives.2) As PM's we always seek prior authorization for expensive turns or capital projects, even though the estimates given to our owner-clients are often ball-park numbers.

You just need to accept a principle of delegation that there will always be things you would do differently then they do.

If I were you I’d buy the investment properties while putting a little extra towards the principle on my primary mortgage each month.