William Ryder cannot defect to the All Blacks. Since about 2000, there has been a one-country ruling. Rupeni Caucaunibuca clearly didn't understand this in 2003 after the RWC when he decided he'd switch to the All Blacks, and it had to be publicly explained to him "well, Rups, this isn't actually possible."
And you're opening up a can of worms I am well-known for not liking the taste of on here.
Which Samoans and Fijians playing for NZ should be playing for the Islands and why?