I think Wyll is lawful good. Karlach is the poster girl for chaotic good.
(One of the problems is that while Wyll does occasionally show signs of a sense of humour, they are few and far between. Mostly, if you go and talk to him he'll say something obvious about the situation and then say something his dad once told him.
Lae'zel, meanwhile: "Githyanki not need a sense of humour. Githyanki training has left our other five senses sharp enough to detect any enemy.")
