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.

I try not to deal with listed properties.3) An investor/agent will not baulk at some of your unusually low offers.

I think SF is an unusual market and I would not decide based on the relative age of the home.

Not unusual at all.

It would be unusual, for example, for a typical residential lease to include the right to cut down timber.

We supplied our tenants with a mini fridge. they were only in the apartment for two days with the mini fridge before they left on their honeymoon for one week. the repairman came today, which is the eighth day, and told me it's outside of his scope and he will have to send another repairman over, but they have been unusually busy lately.

Then I would scour that market deeply and look for unusually underpriced deals.