Re: James shooting Oscar being out of character - hence part of the reason why I ascribe to the scene being him thinking it's Ozpin, not Oscar. James shooting a child? No way. James shooting Ozpin, who lied about Salem as the protags did, whom he may believe has been lying to him about everything, perhaps since he was brought into the know about Salem, who is now here to lecture him about needing to trust and work together? I could wholeheartedly see that.
I can also buy the concept of Ironwood shooting Ozpin far more than I can buy him shooting Oscar, but even then I’d expect better buildup to that. Basically:
A colder reception when Ironwood thinks he’s talking to Ozpin in his office, not a down on his knees ‘Thank the gods you’re here’ reaction. Set up some animosity early. And/or:
We see Ironwood’s opinion of Ozpin taking one hell of a nosedive throughout the course of the volume. Theoretically he could be pissed about the Salem secret, but that’s not what we got. Rather, Ironwood was incredibly calm and accepting when Oscar told him, so instead let us see where this anger came from rather than having it seemingly arrive out of nowhere. ‘I was dealing with the Salem secret but now, an hour later, I want to kill you for it’ is quite the jump
Establish over the course of the volume that Ironwood is having difficulty accepting that Ozpin isn’t around right now and tends to conflate Oscar with him. I know a number of people in the fandom have claimed he does that, but I didn’t see it? Ironwood asking if Ozpin has returned every few weeks is not the same thing as Ironwood legitimately thinking that dorky kid is his boss. In the canon Ironwood is informed that Ozpin is currently gone, that’s Oscar, and far as I can tell he accepts that. So do away with that acceptance and lay the groundwork for him attacking Oscar thinking he’s Ozpin
Personal preference: make it a little less about outright murder lol. I can see Ironwood attacking Ozpin in anger, but again, this is the guy who was willing to let Qrow (who people also insist Ironwood hated because of the “I’d have you shot” line) straight up attack him with a scythe, not even bothering to defend himself. I think taking Ironwood from there to straight up murder in just a little more than a year’s time in-world, when we haven’t gotten to follow his development for a good portion of that, is a leap. So take a smaller step and just let them fight. Let Ironwood have reached a point where he’s willing to attack Ozpin with the intent to release his anger/subdue him so he won’t ruin his plans... and then let Oscar accidentally go over the edge. Ironwood is horrified, but then his expression goes stony because, horrible as it is, it’s still one way to solve his problem. In Volume 8 we could have gotten a moment where Ironwood, not knowing Oscar survived, tries to rationalize that accident by emphasizing that Ozpin reincarnates, so he’s not really dead. This is fine. No big deal. We as the audience know that a) that’s BS, b) Oscar still would have died, but also c) Ironwood never wanted that to happen in the first place and now, coming undone, his mind is scrambling for any possible way to deal with it. Give us a complicated look into a man who loves Ozpin, but is currently furious with Ozpin, didn’t want that to happen to Ozpin, but is now willing to make the most of it.