of contacting the winning bidder (although the auction is anonymous, a simple cross-reference search + a parcel search + Google search easily reveals buyer contact info) to see if he'd be interested in selling the property.

I created a VA LLC with my daughter as the owner (for my anonymity and asset protection), and was planning to hold private mortgages (using another LLC I created), to strip equity and for anonymity.  

@Andrew Syrios is correct, before you scoop up turn key properties that are cash flowing like crazy on paper, visit with local people in that city, live and face to face, not on some anonymous forum but real conversation to see the reputation and if what you are being sold is a good deal or a load of XXXX. 

Here's why: Reason 1: anonymity.

What's the ideal business structure in Texas for sole-owner, flipping business that offers anonymity, tax efficiency and asset protection?

Not to mention you won't have anonymity anyway and quitclaim deeds weaken the title chain.

Most investors are doing LLCs from my experience... but that doesnt mean you have to. there are some liability protections with LLC, along with a little anonymity if set up right. but also some added costs. one suggestion here is just whatever you decide, stick to it. some counties will see a transfer between personal/ LLC or vice a versa as a 'sale' and trigger property tax reassessment.  

The ownership shifts from privately owned to entity owned and Beneficiaries of the Trust remains anonymous and not public record which will not trigger the due on sale clause according to the Garn-St.Germain Act of 1982. 

On YouTube, Clint Coons really pushes a setting up a Wyoming LLC then have it own several LLCs as Wyoming has better anonymity laws.

It's exhausting talking about this.An LLC is useful for two things: anonymity and legal protection.