Well, since Arthur lived, John would have had less of a reason to hunt down Micah, which in turn would have led to Ross not having a reason to take John's family.

But if it did, Arthur and John would have fought against Ross's men in the "final" mission.

I don't think so. Depending on how long he survives (escapes with John and succumbs to TB a few weeks later? Couple of months? Never had it in the first place?) maybe he might have convinced John to mellow out, but in American Venom with a high honour Arthur Charles says going after Micah isn't what he would've wanted, and the others say that they aren't just avenging Arthur, they're avenging the entire gang.