The casting call could have been using a name Erron had earlier in development, or it could have wanted to have some characters' names false. There are a few reasons. And I don't think NRS would have two characters so similar to each other, especially when we haven't seen Salazar at all in the comic yet while Erron's been featured quite a bit. I believe it is more than likely they're the same character.
I agree that it's more than likely. If I had to pull a random number out of my ass for how likely I think it is, I'd say 75-80%. But until that goes up to the 95% area, I don't think it's a great argument for why Erron Black
should not be Black Dragon.
I'm not so sure NRS thinks of it that way. If they don't want to make him a chump, they can just... not make him a chump. Giving him henchmen to order around won't change that; it's not there like there aren't a lot of "henchmen" type characters liked by fans.
You're taking my "henchmen" too literally. Kano needs characters in his camp with whom he can interact in a way that establishes his dominance. They don't have to be dumb drones who don't question his orders (in fact if he's so scary they try to betray him, that could be even better), they don't have to all fear and loathe him, they just have to give us the impression that Kano is a key player in the world of MK. And that's what he's gotta be to make Black Dragon relevant.
Compare the other dudes' prominence so far - Sonya and especially Johnny were two of the main characters in MK9, and look poised to be that again with Cassie thrown in the mix; Sub-Zero had tons of drama (Scorpion's revenge, transformation into Bi Han, Kuai Liang and Smoke running around, getting cyberized, being rescued as a cyberdude) and obviously that's set to continue regardless of which Subz is in the game; Raiden and Liu Kang were
the main characters and at least Raiden will reprise that role in MKX, but Liu Kang will most likely be back too and there'll obviously be in-story hype about that; Quan Chi was the only antagonist who got anything done, including having Raiden grovel in front of him, and is obviously going to be a huge threat in MKX as we now know the invasion of Earthrealm threatens to spill over into Outworld; and Kano... does dick-all in MK9... and then helps Kotal? But he helps him really well? And then he betrays him really well?
You see that there's a level of disproportion here, right? Like it's not even comparable. They've got so much catching up to do with the Black Dragon in the eyes of casuals that there's just no way Kano can do it by his lonesome. For that to happen, he'd have to stop the Netherrealm Invasion practically single-handed, and end the game lying on a bed of money, downing tequila shots, surrounded by naked women. Seeing as how I don't think that's in the cards... they gotta make his faction look cool the hard way.