The video game stuff is common and is a problem. First step is to make sure he knows you (and anyone within 100 meters) hears it clearly. Sometimes people don't realize how loud it is and we'll be embarrassed and that others don't like it. Next time he screams fully scream his name back, him: rage screaming, you: "KYLE FUCKING CHILL". Using the same volume can be important to remind him there's no emergency, everyone can hear, it's weird and interrupts, and there's no reason to be upset.

The general negativity part (especially during activities) you should just be very direct. Tell him to relax, chill, stop 'freaking out', etc..., and tell him what you said here, he's usually not a great bowler and ask why he's upset. Listen to the answer.

He might be complaining for attention, he might feel a weird sense of failure or competition you can help resolve.

A lot of the comments are very 'conflict avoidance' methods, or come of like a weirdly serious intervention. This isn't that serious but it's still annoying, handle it directly without it being a huge deal. None of this "Kyle we need to talk, come sit down, this is a safe space" but call it out when it happens or beforehand and don't treat it like a delicate and dangerous issue, relax and be casual and simply call it out.

There's some states where it's not public record (Delaware being one iirc). I'm not an expert on that sort of thing but I believe the idea is you register it in a state that keeps it anonymous and you can use it in other states.

If anyone reading this has a thorough understanding of how people commonly keep llcs secret and ways people try to get around that secrecy I've always been curious.