I think the correct transliteration to ジェバンニ (Gevanni) is "Jeban'ni" instead of Jebanī as it's on the article. See, the katakana is:
Ji+e = Je (ジェ)
'n (nasal sound) 'ン
then Ni (ニ)
so I guess the right transliteration is Jeban'ni, because ''''Jebanī is for ジェバニー which sounds different.