Disregard.

If your "small Multi" is a 5 unit or higher disregard everything I've written here LOL!

Using an LLC that's tax election is disregarded (or partnership if there are two owners) instead of an S or C corp, will allow you to benefit from cost segs and claiming depreciation as well as other business deductions you are going to incur and will want to write off -- even if you're running at a loss.

The appraisers will generally disregard any value and income from an ADU that is not legal.

Why not create a different LLC that is disregarded for tax purposes and is owned by your Texas LLC. 

Disregard

Reg. §301.6109-1(h)(2)(ii).Here's that Code Section: "(ii) When an entity that was disregarded as an entity separate from its owner becomes recognized as a separate entity.

Disregard the asking price.  

If an LLC has only one member and elects to pay taxes as a sole proprietor then it is a disregarded entity. 

The form allows you to elect to be classified as an association taxable or disregarded as a separate entity so i provided my SSN.