QHow do I resolve this follower's Last Words ability?

APut the evolved Baccherus, Peppy Ghostie faceup in its owner's evolve deck, and the unevolved form into its owner's EX area.

After this follower moves to the cemetery, its Last Words ability triggers. The evolved form loses its link to the unevolved form immediately after moving off the field and is put faceup in its owner's evolve deck. Then, you resolve the Last Words ability, putting the unevolved form into its owner's EX area.

QWhen resolving an ability that says to "summon a Ghost token," can I summon this follower instead?

ANo, you can't.

QWhat does "This follower's name is also Ghost" mean?

AWhile this follower is on the field, it has the name Ghost in addition to the name Baccherus, Peppy Ghostie. Note that having the name Ghost doesn't mean it suddenly gains the same abilities as Ghost, like Storm or "At the start of your end phase, banish this card."