As you were in property management, not sure if you ran your own company, but as you look at it..

Thanks in advance for your insight!   

I like umbrella because there is no worry of being pierced for inadequate separation of finances, if sued you have a heavy weight in your corner who has all the consequences of a defeat, and because usually it is reasonably priced (mine today is not so reasonably priced but I believe it is mostly related to the risks of CA).I do understand that the probability of needing the umbrella policy is low.  

I don't know if they do that, I would assume they do not, but I am not privvy to that type of info.

Do I get the appraisal?

If it was not him sourcing the land, it would be someone else.  

Do NOT put your contact info in the letter!

STR is another concern, many towns have laws against it but most towns do not enforce these laws, just make sure you are aware of them becuase they can be enforced. 

Prioritize your financial stability.

I'd note you're most likely going to do the whole process over again, so don't be surprised if your lawyer doesn't accept your 14 day notice and will send their own.