I've actually been thinking to restructure the TXHASH BIP as an upgrade of CTV. I believe CTV is mature enough to start activation signaling tomorrow. And I'm in favor of doing that. I don't want TXHASH work to hold it back. It can perfectly be structured as a CTV upgrade without much technical debt.

I thought I heard Ark had changed its requirements since the initial idea (which if I remember correctly required CTV for non-interactivity), but this is good to hear I guess.

For lightning it's far less than we hoped, though not useless: there's a lightly-reviewed proposal to use it to avoid a latency hit for Taproot channels. I haven't examined carefully whether it's the ideal solution, though.