Okay, so whilst rereading the page and studying the designs in more detail (and I love the designs so much), I think I caught something I missed originally: it seems like the Twelve Black Saint-Councillor Generals are, in true shonen anime fashion, incorporating their rank numbers into their designs.
The most obvious one was Troll, whose got her ten on a sticker on her laptop, but then I realised Barrister's nose kind of looked like a one, especially if you factor in his mouth as a base and Bea's ear looks like a three.
I feel like I miiiiight be reaching for the others I've noticed; Bishop sort of looks like his sitting position mirrors a four; Pompom's hairtie looks like it could be an eight?; Diva and Roxy look like they might have numbers in their ears as well (although guitars usually have six strings as well).
I wasn't able to draw any conclusions regarding the others numbers and any references although I'll bet that Titan's jersey number is 05.
