Someone Else... it was a hard choice between Tricia and Alie. I think Tricia should have a moment to shine and prove herself o the Gang (but it would make sense if that happened when she was a little bit older)
Ali because she's only been in two episodes (yes I'm counting the TV Series episode. Yes, it was Ali; not the same voice, but it was still Ali) and I think it would be cute to have a reunion where she comes back to the Valley and goes on an Epic Adventure.
But I chose Someone Else because.... HELLO? PTERANO!!! This guy NEEDS a comeback!!