Does anyone know if Rohan Campbell actually put on the mask and played his Myers part in the movie? or was it someone else playing the part?
I’m not sure, but I assume he played the part.
I will say, knowing nothing about the actor or any of his previous work, I was happy to see he has a slight resemblance to Nick Castle. Similar-ish build, skin tone, and curly dark hair. I smiled mid-movie when I saw his hair become more unkempt and fro-ish as the movie progressed. I’m not saying this was in any way intentional on DGG’s part, but the irony there wasn’t lost on me.
he gave the mask a very Castle style stretch
I noticed that too. 
i think he and cory demyers (go figure lol) played corey’s shape
Wondered that myself. The tell-tale sign Ive noticed in any of the new trilogy is the shoulders. JJC has built up alot of trap muscles so his shoulder have a pretty steep angle to them. You see that angle, its JJC