Thanks for the reply, NewBloom!
Finally went with the Catt mix a couple of hours ago. Took a while to do the whole repotting thing - and cleaning the long humidity tray.
While cutting out the dead roots on the Dend (and there were quite a few but also a lot of healthy roots, I think), the rhizome split. It looks like there was growth (or attempted) at two places on the rhizome and each wound up on a separate half. Now, each half has about 4 canes. One looks more promising for growth than the other but the one that doesn't look most promising for new growth has the healthiest cane by far. After soaking that many hours (like 9 - I'm guessing way too many?), the biggest and healthiest cane (which had the keiki on it's tip) had plumped back up. Anyway, both halves are now planted in the Catt mix and the keiki & BLC are ensconced in moss.
I have no idea what will be the final outcome of the BLC but the keiki looks promising. I'll watch for growth, etc. Any idea on when to transfer from moss to mix?
Thanks for the advice. Nice to have someone agree with the direction I took! Who knows, this Dend has looked a whole lot worse in the past. Maybe it has another life left in it!

Worth a chance. It has the most beautiful blossoms - can't wait to see them again someday.