I'm generally an inclusionist, since wiki articles don't take much physical space, and I think this is probably worth more than most lists of pokemon characters.  But to defend against deletionists, you should look for some news articles which reference this study.  There are countless studies (almost all of them) which have been cited by later studies, and most of them don't get wiki articles.  But if you can find some news coverage anywhere which covers this as prominent, that will satisfy them.