We live in uncertain times correct?

The $500 minimum premium is not unusual.

Would these be unusual addendums to put into a P&S agreement?

Its hard for an appraiser to find good comps if a house is unusual.

It's difficult to comp since it's an unusual property.

Elderly buyers, excited, , went to the closest realtor,  and  broker to give us  a contract (they were afraid to leave town without us knowing they were serious:(  In fact, when they entered the office and said they wanted a contract drawn on a house they love, he  (not unusual) asked them if he could take them out to show them some houses.  

I find it unusual that almost all of your criteria are for personal preferences vs which markets have strong appreciation, land lord friendly laws, least natural disasters, etc...

An unusual situation to be sure.This is very different from a custom home builder who has his own crews or subs doing the work, and I felt there was too much opportunity for disagreement or trouble if the work wasn't done to my satisfaction or preference or if the budget was blown, but I was obligated to pay for it and potentially to own the home if Yan were to fail to close on his end of the contract.

Not unusual for them to have 10-20% down payment requirements, though some will also lend all or part of the rehab costs.

And the outcome in the present market is very uncertain.