QCan Rimewind select an enemy advanced follower on the field?

AYes. Advanced followers are not considered evolved followers.

QWhen playing Biofabrication, can I select a faceup advanced follower in my evolved deck?

ANo. Advanced followers are not considered evolved followers.

QI have this follower on my field, and my opponent plays Sylvia, the Condemner, selecting this follower with its Fanfare ability. Can I still engage this follower to deal 6 damage to Sylvia, the Condemner?

ANo. When Sylvia, the Condemner is put onto the field, its Fanfare and this follower's automatic ability will trigger simultaneously, and both abilities will become pending.

When both players control pending abilities, the active player resolves theirs first. In this case, your opponent is the active player, so they resolve Sylvia, the Condemner's Fanfare, destroying this follower.

Next, you would resolve this follower's automatic ability, but since it is now in the cemetery, you would be unable to pay the engage cost, and thus cannot deal the 6 damage to Sylvia, the Condemner.

QIf 2 or more enemy followers are put onto the field simultaneously, can I still engage this follower to deal 6 damage to 1 of them?

AYes. As long as you pay the cost, you may deal 6 damage to 1 of the followers.

QDoes this follower's "whenever an enemy follower is put onto the field" ability trigger when it's not my turn?

AYes, it does.

QIf an enemy follower with Aura is put onto the field, can I engage this follower to deal 6 damage to it?

AYes. Aura prevents the follower from being selected by enemy abilities, but this follower's "whenever an enemy follower is put onto the field" ability does not select.