From what position would you open 9654 or 8765 in 2-7 TD?

9654x is MUCH stronger than 8765.

Interesting.

After making my post I was actually questioning myself about whether I was devaluing 8765x too much.

Would you mind elaborating a little?

I can theorize that I underestimated both blocker and 'unblocker' effects, but I am less sure on how well I am estimating the raw equity.

In raw equity you would be right, and if you were all in pre you would be right, but playability the blocker / unblocker effects are strong like you said. 8765 is also where a lot of snows come from