@p @icedquinn @miscbrains @adiz @m0xEE Yes, you just copy followers collection from the parent post to your reply. The author of top level post is responsible for delivering activities, because you probably don't know who his followers are.
This is described in https://codeberg.org/fediverse/fep/src/branch/main/fep/171b/fep-171b.md
When audience is preserved throughout the conversation, it feels cozy, and no one gets FOMO from looking at broken threads.