Non-expansions... (and a bunch of exceptions you list, but are not limited to).
Seems like a pretty blurry line in the sand. Even blurrier when price 100% has an impact on perception. Skins are an exception but if I told you some skins are $60, would that be predatory?
All gaming IAP that are not full on expansions (not skins, not standalone characters, etc.hm) are predatory