@oldjacket If you are looking for a specific person you want to follow you can search against all followed federated servers to find the person.
@oldjacket I have been off for a while, so I hope this info is accurate. No, the instance will decide which servers to follow, and will show up in the federated timeline. However, you can mute some of those servers, so they all won't be showing in that timeline. I thought a few years ago he was working on a way for a user to add specific servers, but don't know if he did it or not. I will look into it today and try to figure it out.