For 1, I’d say that the only one that should concern you is the “find a fantastic opportunity elsewhere.” Unless your game contains highly objectionable content or the open beta gives feedback that it’s near-incomprehensible due to poor spelling/grammar, CoG will publish it under the HG label, and they’re a thriving, growing business.
For 2, I whole-heartedly agree with Eric. Most CoG fans don’t frequent the forums; the site traffic is, as you said, negligible in the scheme of things. We definitely don’t have anything close to half of CoG customers engaged on the forum; the active forum members at any given time are far fewer than the number of people who buy CoG games. And many forum beta testers buy the games they test (assuming they liked them at beta stage).
I’ve been writing a game for the CoG label for the past six years, and have had it open-tested on the forums at every stage – including now, when it’s basically complete. It’s strengthened the game significantly, and I’m confident that when we do publish later this year, whatever customers I lose because they played it at beta will be a cost well worth the benefits of the test. (If I’m wrong and it’s a flop, then I’ll make sure to update this thread and PM you a warning.)
I can’t speak authoritatively for 3, but my impression is that it’s both to catch abysmal spelling/grammar and to make sure you’ve had some feedback from regular COG readers on how they like your game.
@HomingPidgeon, when a WiP gets to the point where it’s actually going to be a Hosted Game, it needs an open beta, per CoG rules. Whether or not Doug has done a closed beta, he’s got to put the full thing out for beta before it’s published. See the category here: https://forum.choiceofgames.com/c/hosted-games/hosted-games-betas