There are a lot of folks in X-2 whose images appear in X. The Macalania Forest spirits are there - there's one who looks just like Bayra, the harpist, except in X it's a female who guides the butterfly catching torment minigame, and she's voiced by Judi Durand who sci-fi nerds may know as the DS9 computer voice.

As has been mentioned, there are a few little people wearing beaked helmets, just like Tobli, and some Crusaders with silly hats like Beclem's.
Also, on the Mi'ihen Highroad, there's an Al Bhed kid with the same coveralls and mask as Shinra, who says that his dad's onboard the airship. However, even in X-2 this image appears elsewhere - there's a girl dressed like that on the Moonflow banks.

I think it's kind of neat, even though it was probably just done to save time and money. At least it raises the possibility that these are the 'same' people. Well, at least we can think of it that way if we choose.