I asked what they paid for it and they said $4,000 - I asked what DD did you do and they said the county tax value was $6,000 so I was getting a deal… I asked him if he was a Gardener as maybe grow some veggies on it but other than that it’s useless and no one will buy it

Your options are to appeal the appraisal, make it agricultural (community garden or farm crops), raise bees or anythng like that to get the taxes down.

in the SF peninsula and down to Cupertino there was a builder who built about 30k homes in the 50s and 60s  called Eickler these were modern heat in the floor tons of glass interior walk ways with gardens in them etc etc.. very unique ..

Simple question.3 options.1.Keep Garage2.Renovate garage into a small "man cave"3.Take garage down and lay fresh grass for backyard.

Do the walls need a good cleaning or a fresh coat of paint? 

I had a similar experience with birds nesting inside my fresh air exchange vent to an HVAC system.   

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

I am well aware that nobody who bought into this was thinking in purely analytical terms when they bought it -- there was a national media figure freshly retired from a network a lot of people trust at the head of it, waving them in.

Upkeep and maintenance, landscaping, garden and fencing in the backyard.

When you run your comps, are you using comps from when you got the hard money loan, or are you pulling fresh comps before your refinance?