If I attach an Energy to my Active Leafeon (Rising Rivals) and I have a Sceptile (Great Encounters) on my bench, would Energy Refresh remove 4 damage counters instead of 2 because of Wild Growth?
No, because Energy Refresh works for each Energy card you attach to Leafeon, not Energy. So if you attach a Grass Energy to Leafeon, you are still attaching 1 card (even though it provides 2 Energy), for a total of 2 damage counters removed.