Large Lot in Northridge, CA - SB9 Lot Split, ADU Conversion, Prefab Home

[Kaelyn See]

Hey BP! I am starting a very big project that will take a few years to complete, but looking for advice and referrals as I start this journey. 

My family and I purchased a half acre lot in Northridge, CA. As of right now, there are 3 existing permitted structures: main house, detached garage in front (600 sq ft), and huge 2-story detached storage unit in back (2400 sq ft).

Goal (in order of priority): 1) Convert upstairs of detached storage unit in back into 3 bed/2bath (for the downstairs, keep as garage on one side and rec room on other side), 2) convert detached garage in front into 1 bed/1bath for our grandma, and 3) eventually add a prefab home on the lot.

From our research so far, I believe we'll have to do an SB 9 lot split in order to legally build all structures (but we're not sure if we want to do this now, or just convert the back unit into an ADU first then do SB 9 later). We'd like to start with the storage unit in the back, and then the garage in the front, with the goal of finishing everything within 1.5 - 2 years.

Questions/Asks:

1. Is anyone familiar with the SB 9 process, and if so, do you know the estimated costs and timeline?

2. I'm looking for reliable and fair valued architects, engineers, contractors, etc. that can do good job, and in a timely manner.

3. Any advice on anything I mentioned above would be greatly appreciated

Thank you!