I got liability insurance for my LLC and an endorsement that covers me personally.

Fully endorse @John Jackson's advice for anything to do with TX.He's our go to guy for anything we do in TX.

Some insurance companies have Actual Cash Value policies/endorsements to save you on the premium. 

As part of your sub2 closing, you should be getting a limited power-of-attorney (LPOA) from the seller, which will authorize you to receive (and endorse) all manner of payments related to the property, including escrow refund checks, insurance claim proceed checks, etc.

I will not hesitate to encourage or endorse their practice. 

Thanks for the shout out, @Nicholas Aiola.The most prominent REI group in Austin is run by Phil and Shenoah Grove: https://reiaaustin.com/They have a CPA firm as a vendor, but I cannot remember their name.This is not an endorsement from me, as I really do not know much about that firm. 

Not an endorsement of this site, but it does have a rejection letter that is of the basic form that I have been using for years:http://www.totalrealestatesolutions.com/realestateforms/html/rejapp.html

I would also contact the title agent that issued the title policy and ask for an endorsement to change the effective date of the policy through the recording of assumption agreement. 

There a few Insurance companies, that use the Homeowners form with an endorsement for this situation but it is rare.2.

I second @Jordan Moorhead's endorsement of Tower Property Management.