In my case, I have residential rentals in one LLC, commercial properties in another, self storage in a third, and my real estate company operates in a fourth.

In order to have checkbook control, the IRA account will need to be at a trust company that will allow the IRA to invest in an LLC (where you will be the manager and your IRA will be member - an as manager you will have checkbook access to the LLC bank account).

About 5 years ago one of the sellers we bought a multi family from told us about a company that has a lot of landlords like us and we coshare insurance coverage.

I would manage at first to learn the ropes, and then probably use a management company. 

The substitute of collateral was more of a scenario where you sold for $155K, and instead of paying off the $88K loan in your scenario, those funds stayed at the title company and were used on a cash purchase happening nearby in date. 

People have been dropped by insurance companies in wildfire areas and had to scramble to try to find insurance - some using California Fair Plan. 

All title companies work with alot of investors.

(you need to differentiate when a Mark Spain type company is running radio ads to attract business for themselves from it actually helping you out)4) Our TEAM or BROKERAGE has sold "X" homes!

Also note that my company will possibly either cover closing costs if we sell or provide property management for two years if we rent.

You can put a mortgage into a "trust: without triggering a due on sale but again contacting your bank/lender is the best route to avoid any issues.Some banks/lenders or servicing companies change guidelines and even a trust may require other paperwork but the attorney usually facilitates that to be safe.