Are there people that have gotten multiple EX passes?

I did see a post of someone who had two invites before they even did their first EX raid.
This is only anecdotal, but I don't think there is anything stopping people from getting multiple Mewtwo before most of the players have even had a chance at one.

I guess multiple invites possible if you're lucky enough to be in an area with lots of sponsored gyms. I live in the UK & the only place u can get an invite to is Chester, where an event took place a month or two back. This raid testing crap is aload of nonsense, it's all about the sponsorship deals Niantic have in place, the raids are working fine by the looks of it & have been from the start.

I've done two along with most players in my fairly rural area. We have a diehard following here. First week and second week. Caught an both. Transferred the second. Not a wonder. Was lucky enough to critical catch it with a piano. Wish I caught it on film. People, both locally, and online raged.

Same gym, it must've counted the ex-raid as a completed raid because I didn't do any others that week

I have done 2 EX raids, both at the same Sprint location. I did notice that a lot of the people from the first wave, weren't at the second raid. I'd say the number of players at the second raid was about half the amount at the first one.