So this is my Theory behind every Sin arbishop. i know some may not even be possible... but oh well correct me if that is the case
Ley Batenkaitos (gluttony (gourmet)) = (Look Louis)
Roy Alphard (gluttony (bizarre eating)) = (Look Louis)
Louis Arneb (gluttony (satiation)) = i think because he looks diffrent of the others Gluttony sin arbishops, he is a real person. because as you have seen with the White whales. The White Whale can clone himself but a little bit diffrent and way less stronger. so what if Louis is the Real one. and made 2 little buddies to help him eat people. could be possible right?
Sirius (wrath) = MY theory is still that she is the dead aunt of Emilia. It is possible since the author has said that Fortuna has the same color eyes as Emilia. And you wouldn't say that without a reason. + The bandages cover her face has to do something with that right? Though i dont understand one more thing, She has been captured. Why dont they just take of the Bandages... it would have been way more easier.
Capella Emerada Lugnica (lust) = i think this one is a bit obvious though there is more. Could it be possible Regulus gave Emerada witch genes of Lust, and made everybody poison with dragon veins in her family. This would make sense because everyone in the Royal family died because of a unknown reason / illness.
Petelgeuse Romanee-Conti (sloth) = Everything about Petelgeuse is already explained though 1 thing triggers me, The star is called betelgeuse. Not petelgeuse.
Regulus Corneas (greed) = The First sin arbishop for sure, Though i really wanna know how he got his witch genes of Greed...