3) I've heard before that there is a great tax benefit of leasing the office space LLC that you own back to your S Corporation.

Our corporation is approved with a  major bank to finance and improve properties (not hard money).

If the person is not a corporation, that is correct.For example - we operate as a C-type corporation.

If I mainly plan to invest out of state (and not in CA), do I still need to use a California S-corp or LLC?

The increasing Government workforce and Corporate sector employees makes this area worthwhile in providing your cash flow needs.

Sole proprietorship, LLC, partnership, corporation, s-corporation.

Yes, at the end will be a check, but my corporate motto is Real Estate Problems Solved, not Make The Most Amount Of Money On Every Deal.

We still have the loans in our name but the money runs through the LLC & we have been generating corporate tax returns that will help us when we go for financing on larger commercial loans.Hope that helps.

This may not be the strategy you were looking for but it worked for me over the last decade and allowed me to pay off a duplex, leave corporate america and invest in real estate full time.  

We both have engineering degrees and spent almost 20 years trying to work our way up the corporate ladder because we thought that was what being successful was about.