The good subs in your area will likely have plenty of work already and may not even return phone calls.

(If there is a PM, who will manage the PM and the oversight).Who will take care of the partnership return or forward the tax information if its a tenants in common property.Best of luck

Without the high leverage you reduce the top source of return in CA RE which is achieve via the appreciation on a high leverage property.  

I would like to pull out equity from the homes to build either a house on each or an ADU (they are zoned multi-family) depending what makes the most sense on returns and what is feasible.

These specialized companies, easily found online or here, will create your company’s SD 401(k) plan.

Unfortunately, this problem waste a lot of my time that could be spent on other investments.I have used the same tax professional for many years and he is very educated, but also much older than me and it's hard for me to understand all the reasons he has expressed why is better to put the rental on my personal tax returns.

Here's their page called My Lodge Tax, for STRs. https://www.avalara.com/mylodgetax/en/index.html Process returns, Save time and hassle.

Absolutely you can, I rolled over my IRA into a fund making double-digit returns. 

I hit 100% cash on cash return on all these B or C areas and they often outperform my better neighborhood properties. 

It's an estimated cash on cash return given current rental rates subtract expenses assuming 7% interest rate, 10% management fee, 5% repairs, 5% capex and other expenses like mortgage, insurance, tax. it's a estimate to tell you what properties to analyze vs ignoreyou can see the are pockets of negative returns as well as pockets of positive return. this is to supplement the data @Devin Conley provided