With as negative as laser is I'm always hesitant to try and read his run timing. I worked out you can stuff an early run 2 with j1, so I started whiffing it into the air and then reacting to what he does with it. If he finishes with a run normal you can punish with teleport. If he cancels you have some space again.Only just got around to this, my weekend was kinda busy.
So Flash's running man stance, I found out you sometimes can hit him with Omega Beam while he's in RMS. As far as I can tell, if he's just holding the stance he'll low profile Omega Beams, but the beams will hit him if he's actually running in the stance or doing one of the followups (except the low). It seems like you can still zone him, you just have to predict when he's going to go into stance and try to hit him with the beams as he's running. I also had some success by jumping backwards when I thought Flash would do RMS and pressing a j3 on the way down.
I'll have to try more jump back 3, seems like you could confirm into df3 for great damage. Hopefully I'll get another long set with my buddy soon and I'll post my findings.