Gloves of the belligerent skies let's you stack reverberation when you do radiant damage, it's a fun addition. Then you can add the ring of spiteful thunder and the boots of stormy clamor and there's a cloak that also synergies well IIRC.
I'm in a durge playthrough and never talked to Wyll. When I raided the Grove he was among the defenders (near Dammon's shop) and I just killed him there. He just wanted to talk to me after I helped Florick in Waukeen's rest but I ignored him.
Halsin's second is Kivenkataja by Moonsorrow.