As an example, I'm pretty sure leftovers recovery happens before Status. If you could make a list with this, it would be Great. Example (+2 happens first):
(Go on) +2: leech seed +1: leftovers, nightmare +-0: harvest
+8 Destiny Bond KO / Flinch on last Pokemon +7 Weather Damage +6 Leftovers recovery +5 Poison Heal Recovery +4 Speed Boost +3 Black Sludge/Sticky Barb Damage +2 Leech Seed +1 Damage from Status Conditions (Burn, Poison, Confusion, Nightmare, Wrap, etc.) +0 " harvested one Berry!" / "__ was poisoned/burned by Flame/Toxic orb!" message
Taken from the following replays: Replay 1 | Replay 2 | Replay 3 | Replay 4 | Replay 5 | Replay 6