Is it possible that: if you still have the seed for the created lnd wallet, then it's OK that your channel db data is lost, because you could still cooperatively close the channel with the counterparty (because all that's required for that is your key for the 2 of 2 multisig that was funded into)? Well not 'OK' but I mean technically might the funds be recoverable, in that case?

Hmm from a quick search, it seems Rene agrees with this statement: https://bitcoin.stackexchange.com/questions/87463/can-funds-from-a-ln-channel-be-recovered-if-both-participants-suffer-data-loss

As per the comments, this is both technical and tricky and certainly not a button press (and I can't even guarantee it's possible).