Maybe.
Like, this was a good plan by Mesa but it's not without flaws.
First, it's a great PR weapon but I wonder how long it'll actually convince a team of analysts. Unless VEDA doesn't get any idea what the hell happened, then it isn't that hard to figure that this wasn't a Manticorian strike. The missiles came in from a very different vector from the fleet, the Manticorians fired on their own missiles at the incoming wave and were transmitting targetting telemetry.
If you're a panicky, traumatised frontier fleet or Mesan system navy officer who gives a fuck. You see what you want to see, but while VEDA lives through the trauma of an EE violation and are definitely kind of a cult about it, they're also an intelligence agency. Once they actually start looking at the footage like analysts, it's shouldn't be that hard to tell it's a frame job. From there, the question then becomes "if not manpower who?"
And from there, "Look, this is definately a conspiracy."
This probably won't save Manticore from them. Blood is on the ground and a line must be drawn or everyone will be doing this shit.
But the alignment has now committed a full edict violation and it is going to be on. In the longer term that's not something they can wiggle out of.