As logical as your point is, there's no proof that it would be Cecil over any other character. Celes, Terra, Locke... they're all from the same game, they could all be in it, or one could be in it, or someone else entirely.
However, I do have to point out that Nomura recently said in an interview that they were going to "take some risks" with new characters - and they heavily implied that they were going to take characters from FF series that Nomura does not own the rights to. Technically, as the characters are copyrighted to Square, they can use whatever they want, however, they could face lawsuit from the original artist - who would still own some copyright property - for using it without joint permission.
Personally, I'd like to see Terra in it. We need more female characters in Kingdom Hearts. *laughs*
However, I do have to point out that Nomura recently said in an interview that they were going to "take some risks" with new characters - and they heavily implied that they were going to take characters from FF series that Nomura does not own the rights to. Technically, as the characters are copyrighted to Square, they can use whatever they want, however, they could face lawsuit from the original artist - who would still own some copyright property - for using it without joint permission.
Personally, I'd like to see Terra in it. We need more female characters in Kingdom Hearts. *laughs*