Regarding Onion Knight, Ninja and Sage are his 2 EX Forms, specifically chosen cause they're the best two classes in FF3 (actually, according to a Nomura Interview, he said he wanted to use two classes to represent FF3's system and asked around which classes it should be and those two were the most commonly requested.)
and Djinn, there is no Bishop class in FF3. You're probably thinking of Devout/Shaman, and they dress in Moogle Hoodies <.<
Also, while I never heard of that Lord of Vermilion (...well, name sounds familiar actually, but not the concept), that is indeed awesome!