The only reason we're instituting a pref is there are a lot of upfront development fees that we do not want to carry ourselves. 

Like this: https://justaskbenwhy.com/2014/01/05/how-to-build-...It involves some sort of blended institutional/private capital, and a value-add story.Good luck!

When she first contact a financial institution regarding her mother's account, would ask them "do you need the letter of testamentary before going further", otherwise they'll tell her they can't speak to her.

There are a couple of routes you can take in terms of lending but most fall under conventional loans and private institutional lending, which are the loans I specialize in. 

I know that not every institution offers HELOCS, so I'm wondering if anyone could suggest an impartial (non-sponsored) website that offers a feed of all TX HELOC lenders along with rates, fees, etc. 

Typically institutions will lend and encumber the land, or they will lend 60-70% of total cost. 

For private institutional lending/DSCR loans, max leverage interest rates are around 8.75-9.25%, depending on credit score. 

I have never found an actual institutional bank that will do so.You are best to search around for commercial mortgage brokers that have access to these types of private lenders and start asking about their programs.Rates vary... amd right now may well be different from the last time I looked at it due to the wider interest rate situation, but you will be looking at 5.75% to 7.5% depending on the LTV and DSCR in my more recent experience.Hope that helps, and good luck.DG 

True hard money lenders likely will not want to be in 2nd lien position to an institution.

@Genele Ekinde most "institutional" lenders will use the FICO 5 model.