We're able to afford the place as a 2 flat, but still pondering legal options for monetizing the garden unit, if any exist. 

Are you in a position to manage all of this? 

Which I think is why MOST properties don't sell for that close to the market value.its not that much different from a stock option right?

I buy and sell homes and wholesale Lease options .

I can see the numbers are showing positive cashflow if the property goes on rent.

Each person can provide a recommendation for the appraiser and the other party agreeIf you cannot agree on an appraiser then you sure as you know what will never come to an agreement on the price.Another option is to list it and you have ROFR

People getting wise to wholesalers that will only close IF they can sell property for more than contract price, and use option period or weasel clause to terminate.  

Almost to many questions really, but that's fine and viewed that as a positive. 

I personally find that the metro areas such as, Arvada, Westminster, Wheat Ridge, are all great options depending on your criteria.

There are some great options and if you are newer to the re industry it can be helpful to have the right resources so you are covered.