At the end the two of us were just shoving things in garbage bags and not caring what was ending up in his storage unit.  

An eviction action can always be vacated - but an eviction can never be made retroactive to when it 'should' have begun.As I see it:  as soon as you post notice the "28 day storage" clock starts running.  

It could be anywhere - I just use it as office/storage/inventory for my business.

Just assign your contract to the end investor for a nice fee and let him/her go to closing since they're now in your shoes as purchaser.

By putting myself in the sellers shoes, I think I'll take the deal so that I won't have to worry about wasting more time and money on the remaining duplex. 

If I were to put myself in the shoes of a successful business person (insert type of business).

I'm not saying you won't be successful in this deal but if it does bite the dust it may be too hard to continue on and pursue RE.If I was in your shoes I would find a property you can fully analyze and protect yourself agsint with inspection, walk through, title insurance, etc. 

In your shoes, that would be a no-brainer choice.  

I am in similar shoes.

While your costs should not be as high as a new build, in your shoes, I'd probably budget at $60-$75 per sq. ft. depending on the amount of structural alteration and restoration involved and the level of finish you would be placing in the units.