I would be totally fine with dumping Halsin for Minthara, since I never really interact with Halsin much anyway. I’d love to have that option on a playthrough where you don’t slaughter the grove. But there’s one thing that confuses me about the datamined ultimatum that Halsin gives, and just the whole notion that Halsin might leave your party in general.
Act 2 spoilers
Without Halsin, how are you supposed to lift the Shadow Curse?