Anita Adams’ ambition sounds simple enough: the Seattle homeowner wants to build a second, four-unit structure on her property so she can give her adult children, father-in-law, and potentially other family members a place to live in the city’s historically Black Central District, where she has resided her entire life. The 49-year-old government worker and her husband can afford the project with financing, which she expects would total around 2,200 square feet, though she may have to rent out one of the units for a few years to help cover construction costs. What she can’t afford, though, is the extra...