With just these numbers to go on, if I felt the neighborhood is solid/trending up and not down and assuming your rent projection is realistic, I'd buy it. 

As seen above, average rates were in the 6.5% range and projections for both MBA and Fannie showed projected higher rates before they came back down.

There are risks as you are tying up your primary residence in the project.

The numbers are tough and it's hard to account for all unforseen expenses.

Finish the project, take great pictures and go live quickly. 

I am on the same journey and as I have been battling over whether partnership or hard money makes sense for my own projects.

I reviewed the SB9 legislation, and it states that properties occupied by a tenant in the last 3 years are excluded from SB9 but only if the project includes demolition or altering more than 25% of the exterior structural wall.

Quote from @Paul Dashevsky: Just finished my SB9 and ADU project in Los Angeles (San Fernando Valley).

since as part of the project you are going to need an architect and civil engineer, I recommend starting with them and ask them who they have worked with for zoning.

One of the most common mistakes beginners make is jumping into large rehab projects without having a solid team or boots on the ground.