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. 

In Oregon their is an attorney but usually only one or two and they are at corporate headquarters and only handle things at a different level never with vanilla closings like in other states.The other prominent thing that is a big help in Or.. is the Customer service ..

At minimum you’ll need an architect (to design plans that meet code), a general contractor (to build), and potentially a civil engineer (if there’s grading, utilities, or drainage work). 

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

In short, it’s possible but not automatic — check the zoning map and consult an architect or zoning attorney before buying.

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

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

Interesting idea, but I always get cautious when a project starts with a luxury property and a famous architect's name.

And the guests I get are smaller families than in the summer, and they have all been good guests with less wear and tear than in the summer.On your first 5 photos that show up on your main Airbnb page, I would also recommend changing the hot tub photo to one with more of a closeup of the hot tub and have it bubbling, so it's more prominent. 

A major error on the part of the architect.