Celebrity does not have much "roving classical, jazz, blues, rock musicians" especially on the E class ships, a LOT of canned music.
Celebrity does have good to great shows in the theatre, 2 shows per night, most are very enjoyable.
All Celebrity ships have a running track of some sort. On longer cruises (TA's for example) they do allow the use of either a MDR or Spec. Rest for game playing but have never seen a continental breakfast served, just a coffee & water station.
Celebrity is charging crazy rates at this point so we have moved onto Oceania and also have a Princess TA booked.