Exactly, yes.

Is there any indication for the lemmy.world people to notice that the instance hosting the community is gone?

I don’t think there is but I remember the lemmy devs saying they’ll add a warning at some point when a community can’t be reached.

Do all the other Lemmy instances keep a copy of the content from lemm.ee?

Yes, but it only keeps text and links, any images uploaded to lemm.ee will be lost. Any community in lemm.ee will still be visible but nobody outside of your instance will see anything you post there so they’re effectively dead.

What, you don’t put eggs, snails, an entire fish, and a whole lobster on your pizza?