Attorney-client privilege does not apply to future planned crimes:

https://www.americanbar.org/groups/litigation/committees/trial-practice/articles/2014/spring2014-0414-crime-fraud-exception-attorney-client-privilege.html

Even when something is supposed to be confidential - I don't mean with attorneys specifically, but with psychologists/psychiatrists, for example - it's never 0% risk. I recall a number of posts on this board over the past 15 years discussing cases where a pedophile went to a therapist and they then ratted them out to their workplace, wife, etc.

Regarding research, a "real" researcher using data from a study they were conducting on pedophiles for the purposes of exposing them publicly is the one thing I wouldn't worry about, though that should be a non-issue - identifying data should never be collected in the first place (really regardless of the topic of the study) - so this should not be possible anyway.