Properties with no mortgage tend to be lawsuit targets. 

Are you targeting a certain area of STL?

I simply recommended the seller finance structure based on the current market rates to make it easier to sell since he has better rates than can be gained financing traditionally.

Quote from @Nathan Gesner: If I've said it once, I've said it a thousand times.Nathan, while what you state works 90%, when you reach a certain level you become a TARGET for predatory attorneys and professional plaintiffs.

As long as the total of the replacement properties meets your reinvestment target you'll still defer all tax. 

Im sure theres easier ways but that the best i knew how to go from rags to riches so to speak!

They loosen the guidelines last year and made it much easier to get ADUs permitted.The other major risk by not permitting is if you decide to get it permitted later on, it is likely going to be more expensive.

You’ll find properties specifically zoned for short-term use, which makes your life so much easier.

To managed it a bit easier (when you grow to more than a dozen), it'll be better to have one online login and manage all 'child' accounts.

This new area is basically double the housing cost then the first, but I think finding the team to manage will be much easier.