How will this migration actually work? The comments transfer over?

If Piped is basically a proxy to access YouTube videos, who pays for this proxy (which shouldn’t be cheap)?

I’m out of the loop on this subject. I know Onedrive previously offered 15GB to free users, then strunk it to 5GB, but kept the larger amount to legacy users.

Have they made another reduction recently?

Lemmy taking over as a protocol would not be a bad thing, because by design it promotes the creation of multiple federated instances. At least the UI woukd be standardized, lowering the user friction in case he needs to migrate.