Each time the sound is audibly different (which is obviously the case with a concert), it must be a new recording.
I would keep the titles as on the printed tracklist.
I would put the section titles (live this place, live that place) in the recording comments.
An example:
These live comments are not visible like this in the native MusicBrainz release page, without INLINE STUFF user script, though. You have to click each recording to see it.