Seattle basement remodel advice

[Matthew Knorr]

Hello,

My wife and I just purchased an older 1927 house in Seattle, WA with the intention to use the BRRR strategy. We are living in it during the remodeling process . The goal is to take the 2 bed 1.75 bath house and split it into two units. the main floor and attic will become a 3 bed 2 bath unit and the basement will become a 2 bed 1 bath unit. Two problems, the attic peak is only 7' and the basement height is about 6'8" on average. In Seattle, the height requirements for livable space is 7' minimum across 50% of the space not including areas that are less than 5' high. My main questions for this post are regarding the basement remodel:

1. Digging down or jacking up the entire house, what would you do to get to the 7' height requirement?
2. Would you keep a stairway between the two units to allow renting the house as one unit in the future? I have seen this in a couple units I have rented in Seattle.
3. Does anyone know a good structural engineer/architect in Seattle who can design an affordable attic and basement remodel for an older home?

Thanks for the advice!