Well, in case anyone google it in the future.
If you pickup the idol, I did just after rescuing the little tiefling at the beach and without speaking with Will, all druids go full genocidal against every tieflings, Will and yourself. I started the fight against 2 druids only. Easy to kill and then ported to camp to longrest. A popup message of the save the refugees shows up saying that any remaining survivor left the grove. Then you can go MInthara and say her about the grove location, and without any fighting in your part when you come back all druids are dead with the remaining bodies of the tieflings and you have a party in your camp with the gobbos. The dialog is quite buggy couse your companions act if you did all the genocide but thats it.
Ofc, that still prevent you to recruit Will and Karlach even if you haven't reached her before that "situation". But i felt less dirty than betraying Zevlor like the "intended way" and when you are in the creche all reference to the massacre are about the druids, none about the tieflings.
Is not perfect couse of the glitches on some dialogs as mentioned but feels like a more neutral way to experience with Minthara without going full geno.