A bit about me:I've been a practicing architect for 15 years, mainly in commercial architecture. 

The mistakes feature most prominently as the pain of failure and not making money lingers on for a long time while the successes fade pretty quickly.As to deal analysis I would have to say that as real estate appraiser - MAI candidate (member Appraisal Institute Candidate member - the course work and experience of appraising lots of types of commercial and residential property over 10 years or so gave me a solid understanding or how to look at various properties by the numbers. 

We have a nice, large lot (7500sf, level, no trees) in a prominent NR3 zoned location in Seattle, currently serving as a grandfathered duplex.

Regardless you’ll probably need a good attorney and architect.

A major error on the part of the architect.

They would be posted prominently AND initialed and attached to the Rental Agreement at signing.

@Jennifer Kim I can recommend a few SB9 architects and contractors in Los Angeles...please DM me. 

BiggerPockets used to advertise more prominently local meetups hosted by members.  

Sadly, due to architect oversight there was a conflict between the zoning approvals and the building code which requires a pivot to a new design. 

Do they have a relationship with an architect and structural engineer who is reproducing the same plans at a discount rate and saving time because the plans have already been produced and vetted by the municipality leading to quicker permitting turnaround times?