[Angamb]

because he had just joined them after Alkali Lake.

Rogue and Bobby's uniforms were probably coming already, or maybe Xavier already had them, for when they "were ready". Its not the same case as Kurt, definetly.

For me, Kurt ended like the new team member. That's what that last scene meant to me.

Just because Fox and Ratner left him out doesnt mean he didnt become a member. At least in my book.