QIf I put Lucifer onto my field with this follower's Fanfare ability, do I give my leader +4 defense at the start of my end phase in addition to putting Lucifer on the bottom of my deck?

AYes, you do.

QIf I put a follower onto my field with this follower's Fanfare ability and then evolve it, do I still put it on the bottom of my deck at the start of my end phase?

AYes. Put the evolved form faceup in your evolve deck, and the unevolved form on the bottom of your deck.