I have been onboard with this group before (we were not part of the group) and I can tell you that they 1. will have shows in the main theater during the day, 2. some shows on the Lido deck in the evenings (it will be roped off and you can still walk through the area or sit way off to the side) and 3. expect them to take over the Crow's Nest ALMOST EVERY NIGHT (either as a private party or just hanging out), and 4. private events like "meet and greet" during the cruise.
FYI - Once DH and I walked into one of their main theater shows by accident (no sign by the door that it was a private event, we just heard music), sat in the last row way up in the balcony and a few minutes later, 2 of their organizers demanded we leave immediately.
Being their first cruise post-covid, it's hard to know group size but it was about 100 or so. If you're Irish and like Phil Coulter's music, it's worth looking into this group - oh, and only the name is Tranquil...it's a rowdy Irish group. 😀