Traditionally most seller financing only involves a short period of 3-7yrs of seller financing at white point a balloon payment would occur which forces the buyer to refinance before the balloon is due, essentially guaranteeing the seller wont be stuck holding a mortgage for 30yrs. 

How bad could he have been harmed if he is not taking his money back?

If your long-term goal is always going to be to buy multi-family property in Connecticut, then I see no harm in getting started now.

The taxes will come due when the property is sold unless a 1031 exchange occurs (which in effect moves the tax due to the new property) or a new cost basis is established due to death.   

I will recommend just keep it local.Pros including but not limited: 1. you know the area better;2. you know more people that can help you;3. easy for you to manage;4. easier to manage by yourself, you'll also learn more while you managingThere always be new problems or challenges occurring every time you make a new investment in real estate even if you're experienced.The only cons might be that you have to take lower cash-to-cash ROI on paper compare to other places.

That is a different problem.I think my idea was for the renovation to occur while they held Title. 

If they did not find a new tenant, they have financial harm until the unit is rented and they have a good argument to hold you accountable to that. 

Either way, the only way tenants can be evicted in Cleveland at the moment is if they commit a felony on the property or they threaten the neighbors with bodily harm.

How do folks normally establish how a payout will occur with investors?

I do have plans within the next few months to be creating a separate JV partnership LLC, and when that does occur, it will 100% be done through an attorney, and I will also inspect my original filings at that time.