Assuming that you start with the best possible values/preconditions before the Second Gathering, there seems to be a narrow path through this event where you at least achieve all the "secondary" goals. You'd still end up with [Light Collateral] damage, and need to have Orcent win all the solo fights (i.e. not spare the Orgasmic Champion, with unknown future consequences).
The idea is to gain +5 Orgasmic from Balia's choices (pushing Orc Attractiveness), +5 G. Philon from reducing slave presence at the orgy (accepting the penalties) and +4 G. Rodak selecting "Extend olive branch to Lustlord" and "Favor Rodakan dishes".
It's clear that G. Philon needs to reach 10 before the Succubus Council (for the trade agreement) and G. Rodak should be 5 (to save the entire Lustlord harem). If you carefully navigate through your decisions, you can end up with those thresholds, plus G. Influence = 16 and G. Orgasmic = 11 (a total of 10+5+16+11=42 points). Influence 16 is decisive for reaching the best Succubus Council value (9). With that achieved, G. Orgasmic = 11 is sufficient enable OE Slavery Reform (9+11=20).
Day 1
- "Hint for Esthera to call out", "Support Anak Xerces", "Remain Silent", "Extend olive branch to Lustlord"
- Aka makes all relevant contacts (Orcent, Grubbak, Unsuccubus, Vunne)
Day 2
- "Prioritize attractiveness"
- Solo Fights: all (=5) victories
- [Investigation Round #1]
- Elite Fights: "Add more warriors", win all (=4)
- Mass Infantery Round: should be able to achieve best possible result (23 Balia Points even without Orcsphere, 26 if owned)
- Ask Esthera to "Reduce slave presence"
Day 3
- Make sure to secure another +1 G. Influence with "Join the lesser kings". Even at -2 Orgy Points starting value Nalili can still achieve the best outcome (with the proper choices).
- [Investigation Round #2]
- Visit to Climax (Orgasmic Capital), work to maximize Riala Points (13)
Day 4
- Anak Gauntlet Recon
- [Investigation Round #3]
- Anak Gauntlet Race
Day 5
- Nyst Event
- [Investigation Round #4]
Day 6
- "Favor Rodakan dishes"
- [Investigation Round #5]
- Second visit to Climax (Don't forget to talk to Vunne to maximize her RP)
- Culinary Competition: work to maximize Iris Points (9+ for best outcome)
- Pan Succubus Council: Council Score 9 ("we're in an excellent position")
Slavery Reform 9+11=20 -> [OE Slavery] On
Orgasmic Overall should reach 32+ -> Lamia Reform, [OE Lamias] On
Phlion Negotiation passes all thresholds -> Trade agreement, [Philon/OE Agreement] On
Council Overall should easily reach 16+ for the best result
Day 7
You end up with Gathering Overall = 13 in this scenario -> [Light Collateral] On. While it may be feasible to push this by another point (to avoid collateral damage), it would definitely harm one or more of the other objectives. With Vunne RP = 7 and G. Rodak = 5 the Lustlord's harem will be saved.
I did a playthrough of this on TLS 0.55.4, and it all worked out as expected.