On the rugby attendances. Connaught seem be really well supported compared to other provinces. Leinster and Ulster have a big advantage being in huge population centers of Dublin and Belfast. New stadium should give Connaught a big lift.
Munster often get 5/6,000 at pro14 games. They always announce 12/13k but that is a tickets sold figure and they sell around 10k season tickets every year. Seems like most season ticket holders buy for the big european games and couldn't be bothered with the old second strings in the pro14.
Munster played Benetton in a pro14 quarter final last year and Thomond was much fuller than usual and they announces 10k. It was a game season tickets didn't cover so it was an actual bums on seats figure.
Season tickets aren't huge in the GAA. I'm not sure if it if they do the same thing and count season tickets in the attendance whether they attend or not.