How can I import data from buddypress to Discourse?
Not all of BuddyPress’ data has a logical equivalent in Discourse. But if you’re using BuddyPress together with bbPress you can migrate your forum using this script:
For groups migration, you’d probably have to extend that script. It should be possible to migrate the user groups, but I don’t know where the activity stream would go in Discourse. That’s just not a thing here.