We keep seeing conflicting views but my personal experience with buyers indicates that the outlook is positive.   

Since you have no contract, there is nothing that says you do not have to pay if you are not satisfied, and your spreadsheet would seem to indicate you owe him the money.Similarly, since you paid him for previous work on the spreadsheet, and the spreadsheet shows you owe him for additional work, your argument is not very strong.

I have some good examples I can show you about Kansas City investments that indicate good returns on your exchange.

Population growth, job diversity, and low DOM (days on market) are significant indicators.

I have seen a tax attorney on YouTube specifically saying you can take a full year of depreciation even if you buy in December but all I see in the IRS publications indicates that you have to prorate based upon the time it was available to rent.is there a rule I am missing?  

I have looked at Hopatcong however despite allowing STRs, it has language that requires the STR to be the principal residence of the owner as indicated by something such as a diver's license.

At this point I know their income is sufficient, they have indicated they dont have a criminal issue, bankruptcies, and evictions. 4.

I haven't done a 1031 exchange, but may in the near future and the small amount of research I have done on it seems to indicate that some qualified intermediaries only do the intermediary task (hold your money while you close on the new deal) and some try to do other tasks as well, like facilitate you finding the next deal, etc. 

As others noted, most municipalities issue future zoning maps which indicate the direction the local planning commission or equivalent wants to take their zoning and if your plans are consistent, that's generally a good indication as well. 

The historical appreciate indicates it will not keep up with inflation and therefore loose value in inflation adjusted dollars.