You need at least the SCB backup file from the previous Lightning Node
As a member of the LND team described eloquently:
“ …you only need the SCB (channel.backup) file. What the doc (the disaster recovery doc I linked above) is referring to is that if you are able to recover the channel.db file from a node that otherwise crashed (and if that file is fully intact) then you can restore the channels to full operation again, as with the SCB file you will need to ask all your peers to force close.
And in the case of zombie channels (the peer isn’t around anymore when you attempt recovery through SCB), even an old version of the channel.db file can be useful for manual recovery (never start a node with an old channel.db file!)…”
I have this described here: Telegram: Contact @getumbrel
Meaning, a lot can go wrong with the offchain channel migration, that’s why this automated recovery method with SCB is currently one of the safest and most reliable methods to recover all funds specifically back onchain,
So because you crashed before we had automated recovery Fred you’d need to have that drive and that SCB file at least still to get that channel back (believe it was 250k sats? Or ask your peer maybe they can run a command called remote sweep if they are a good samiritan to assist), otherwise with the seed you only get what was onchain not what was in channels