Ultimately we decided to completely replace and revamp both the entire carwash tunnel equipment and also completely remodel the customer lobby are. reversed the staircase to allow for a separate entrance to access the upstairs office space to rent out separate from the washWhat was the outcome?

I am a remodeling contractor and have a long time friend/acquaintance with significant resources and capital.

Doing a remodel on a 750sqft unit and am curious on what people use to haul the demo away?

You also will not get full value for the SF associated with the bath remodel. 

Other than price, what seller-funded incentives are working to move a remodeled single-family home?  

Make your cash-offers, remodel/value add (ideally), and then cash-out into a fixed rate.  

Full interior gut and remodels?

We used the money to pay her car note off and did our primary home remodeling so now she's happy and on board for future deals.

Can't recommend @Joseph Cornwell enough, he helped me buy my first duplex in Cincinnati and he has a contracting business, so he can give you advice on repairs, remodel costs, etc

I'd start out by looking for contractors that have working knowledge in the remodel business as they will know the scopes required to complete the project.