We do own our primary residence but as far as investments go, this is not the place at the moment.

Some questions I have are:What I would want to know is what is the LTV on the primary loan and what are the loan terms. 

I am not one to use a HELOC on my primary to invest .

There's definitely a learning curve but as long as you're prepared for it all both mentally and financially, it can be extremely rewarding.Also starting up my first STR here in CA soon... just my ADU we're almost done with at our primary.

I think the investor-focused agent is one that understands investor needs vs. buying a primary home- very different ball games I think.

My first thought would be to see if I can land one of these specs, have one of my contractors finish the last 15%, move in this myself, and then list my current primary as a rental property. 

I found the county criteria which reads as:"Property must be minimum of 1 acre, meet the underlying zone district, have adequate parking, meet the requirements set for by the Wildfire Hazard Overlay District, have valid water and sanitation, have legal access, use the primary dwelling unit, be free of violations, and have no substantial detriment to the intent of the Zoning Resolution."

I think it actually matters more of the distance from your primary, but I would definitely talk to an investor-friendly lender to see their thoughts. https://www.biggerpockets.com/business/finder/lenders

I am getting mid 5s on a conventional primary owner occupied loan

If you are ok living with roommates another option is house hacking where you buy a property as a primary and rent out the rest of the property then move out after 12 months to acquire your next one.