DI away from M2's dthrow
Dtilt more
Don't be too timid with the Fsmash, it's roy's kill move and realize you need to use it. Realize also that when you miss you are typically going to be punished for it, and learn to accept that.
Don't be afraid to space outside of SG range on iori's shield. M2's grab range is pretty poor (in front of him), and you can pretty easily dtilt and jab his shield without worrying about being grabbed. In that situation Iori will roll so pay attention for that and try to punish him for rolling
Save your 2nd jump when recovering sometimes. Several times he came out and killed you because you 2nd jumped too soon. Basically learn to recover better i guess. Recovering is a skill just like edgeguarding and it seems to be your weakest suit.
What's with the charged B's on the level? M2 should never get hit by them when recovering. Your best bet against m2 is just learning when and how to apply the fsmash (and other smashes).
A lot of people say M2 beats roy, but i think it's an even matchup cause they don't know how to DI.
EDIT: Oh yeah, JC your grabs and CC more. Also I'd be willing to bet empty SH -> Fsmash would have wrecked Iori.