1) Yeah, there's definitely no laws of any kind that require them to disclose anything of that nature. They don't "have" to announce anything. They do so by choice.
1a) Yes, you're most certainly right that the sites are spewing garbage again. If you read closely, all it really says is somebody close to Punk told somebody that he is definitely done with the WWE...I have no idea how that got turned into he was granted an early release.
2) Just to reiterate, the law has nothing to do with this. If NBC (or whoever signs them to their next TV deal) feels they were mislead or outright lied to during contract negotiations, they would certainly be afforded the right to void the contract, but there would be no scandal legally speaking. To be clear, there is absolutely nothing criminal about this in any way, shape, or form.
3) The fact that he looks very relaxed probably just means he's happy being done with the WWE. He never appeared to be a guy that loved what he did, like a John Cena. He was never going to be a lifer. He had a lot of problems with the WWE, he always has, and it was just a matter of time before he left. Him being relaxed now that he's out of that situation is not surprising.
4) Yeah, they're definitely not paying him while he's gone. Definitely, definitely, definitely not. Why would they give him a dime when he leaves the company on his own and refuses to work? Not happening under any circumstances. They may have to pay him if he they sent him home, depending on the language of the contract, but there's no contract in the world that sees an employer get paid when he refuses to work. Certainly not in this country, certainly not in the WWE.
4a) No compete clauses don't apply to expiring contracts, so there wouldn't be any 90 days on top of the 4 months that he'll be sitting out for this contract. No compete clauses only apply to contracts that are being terminated early.
5) It's certainly possible that he'll decide to come back someday, maybe this summer, but I wouldn't be surprised if he was done with wrestling for good. Like I said before, while it's something he's very very good at, he doesn't really have that personality to keep getting sucked back in. When he's done, he's done, he'll move on to whatever's next in his life and not look back. That's always been clear, even before he walked out. Is he done now? Obviously, nobody knows that yet. But I wouldn't be surprised.
Now that that's out of the way, in response to the topic, I really see no reason for the WWE to address it. The Rock/Austin situation is apples and oranges. When Austin walked out, they knew he'd be back. And Rock was his rival. Having Rock come out and rip Austin made sense, storyline wise, even if it was a real life situation as well.
And while I understand the point about Daniel Bryan addressing it, because the crowd will be more hostile towards anyone else, it makes no sense for him to address it. He's never had a beef with CM Punk, he shares the same fan base as Punk, and on some level he probably agrees with what Punk did. Or, at least, he understands it. With Bryan coming out and ripping 'the machine' every week, it'd make no sense for him to come out and rip somebody else for standing up to 'the machine' like Punk did. Especially given the fact that one of the reasons given for Punk's walkout is the WWE's treatment of Daniel Bryan! IF it's going to be addressed, it'd have to be John Cena. That would be your Rock/Austin promo. But, again, why address it at all? I really see no benefit to it. Let the crowds chant, they're going to do that even if Bryan or Cena does address it, it will all die down eventually.