"Is confidentiality required from a Church concerning someone's record of Church membership, participation and/or attendance?"
I would think not, as baptismal records, marriage records, death records, etc. would all be considered public information. The RC church even posts wedding bans before marriages so I don't think any of that stuff would be considered confidential.
As for attendance, unless you use an envelope with your name on it, who would be able to keep track of that? The most would be if you were registered at a Parish.
Thanks for responding, Jocon. That all makes sense, now.