An umbrella policy across all of the properties will most likely be more than the savings you'd generate by removing your personal property. 

However, I have taken the route of getting an umbrella policy.

It's not a big deal though, as an umbrella insurance policy probably gives you more protection than a simple LLC (any lawyers can chime in here and tell me I'm wrong).  

If your umbrella does not cover over the rentals have your agent check on PersonalUmbrella.com. 

Another coverage to consider is Water Backup.I would maximize the Liability coverage and consider an umbrella above it

There are a couple of ways you can hedge this, the first one is via an umbrella policy by your insurance company (you can get one that covers all of the assets), two the fact there is a mortgage means that you do not own the asset free and clear and have only limited equity so if some tries to sue you it may not be worth it.   

Forming a new LLC would allow someone to open a business checking account and track all of those expenses under one umbrella. 

Get liability umbrella for insurance and you also get insurance from some of the booking platforms.   4. 1031's work on STRs.Cheers!

However, you could also get an umbrella insurance policy instead of opening an LLC and moving the financing (if you have any) to the LLC.

I haven't done this yet because I'm not sure if I can get an umbrella policy to cover all my assets especially if I have some in a trust and some in LLC, or if I should just put them all in the trust.