I'm wondering what am I allowed to do with the 150 square feet besides ingress/egress.For example: Can I add 150 square feet to the structure, including an exterior door, and then use the extra 150 square feet for a kitchenette?

For my company Lincoln Square has seen some of the largest increases. 

Quote from @Sara Frank: Surprisingly, there are pockets of Washington DC that can net you significant cash flow using Section-8.

Quote from @Ashish Wa: Quote from @Jonah Hartsburg: We have collaborated with Hemlane to do a lease-up for an OOS investor.

Smaller square footage compared to Whisper as a 4 bedroom, which might limit potential rental income.b) Whisper, San Marcos:Larger home with an extra study room, which is a valuable feature for potential tenants looking for office space.

The land is on a 20-year lease.Being in WA state, options are limited in my area and homes prices are somewhat out of reach. 

My name is Rachel - I currently live in the Washington, DC area but have ties to Spain and am making it a target to move there farther down the road. 

You are making this more complicated by trying to fit each square idea into a round hole.Real Estate comes in two flavors.

I would appreciate references to experienced professionals (architects, arborists, GC, surveyors etc.) who can help me negotiate and get permits for a short plat in Bellevue, WA. 

While NREIG claimed that the property was under insured; NREIG was the one who determined the square footage and value, we had nothing to do with these details.