Can a Cue List be activated by MIDI, or does it have to be active in order to listen to MIDI?

Imagine that I have 3 songs that are going to be played, and 3 cue lists assigned to playback buttons to handle the sections of each song (Verse/Chorus/Bridge/etc.)

Question 1: Does each song need its own cue list, or is this simply an organizational preference?
Question 2: Can MIDI activate playbacks, or does every playback assigned to a song need to be fired up before the song?