I think my ideal investment is a fix up duplex.

You might have fixed it up nice but modular homes here have serious ceilings on value, even on a permanent foundation. 

Spouse and I are small time real estate investors, we are looking to do some fix/flips in Texas.

I see a fixed rate product advertised here on BP but not a HELOC type of product, where you can draw and repay on commercial property.With the DSCR loans, the lender requirements will change from lender to lender.  

If this is a legitimate mold issue: need to get it fixed.

And you’d know which houses to just abandon because even you can’t justify fixing them. 

I'm hoping to secure a fix & flip for my next deal and I'm looking out of state (specifically in Oklahoma).

I can agree for the most part, but I do have a prime-time lender who will consider non-recourse for fix and flip and ground up construction. 

My research guided me to form an LLC to hold the properties during repair/rehab (I am buying properties that need major fixing) and move them to another LLC where I will be collecting rent. 

Norada’s promissory notes generate predictable monthly passive income transferred to the investor’s funding account via ACH,” ( Link ).Santarelli confirms these fixed, double digit returns in a detailed YouTube video presentation (Link, at 35:08).