If something happened, would I be covered under liability protection with my insurance.5.

For landlord insurance - just go to like Allstate?

Bump up your insurance line-item - commercial insurance for STRs is something you'll need, and it's notably more expensive than a regular homeowner's policy.  

Does anyone have an idea of what I might expect to pay each month for insurance costs?

You will still have roofs, AC units, appliances, insurance deductibles, etc on the smaller properties.

Most advice I have read is to start looking once you get past the 5-8 unit mark but honestly a proper sized umbrella policy will serve the same purpose.

But if they don't pay their rent, I can't pay my mortgage, pay my property taxes, pay my insurance, pay my managers, my workers, etc. 

Just to throw out a property for example:100k Purchase price10k in repairs130k ARV1300/month rent1313/yr taxes550/yr flood insurance est800/yr insurance est10% management fee...

I was a little surprised how much the operating costs really are when I try and project what I'll need in 10 years to not have to pay out of pocket for big expenses plus the basic outflow (lawn, lic fees, termite inspections, insurance, taxes...)Here's my question, the property nets 1500 per month after I pull everything out.

Without the contract being released, then title insurance wont be issued for the property if a title attorney is aware of the unreleased contract.