In Heathenry, the closest thing we have to excommunication is declaring someone outlawed and erecting a níðstang against them, but this isn’t done very often. Most of the time, if someone does something reprehensible, the community will just spread the word that they don’t condone this person’s actions and recommend that they be excluded from big events (like Trothmoot), but I’d say that goes for the Pagan community in general. That’s more for big public figures who are acting like idiots, though. If you’ve just, say, ticked off a member of your kindred, you can always join another (since each group is autonomous).
As for apostasy, this isn’t really an issue in a tradition that is more focused on orthopraxy. One person in a kindred might believe that the gods are metaphors, and another might see them as literal beings, but as long as they’re both doing the same thing during ritual, there isn’t really an issue.
And of course, there are solitary practitioners like myself who aren’t beholden to anyone but themselves when it comes to belief and practice.