Greetings! Thought I'd drop by to give my opinions.

: Very volatile matchup, I've had some nasty experiences. Speed and range really put pressure on us 2D Masters to have a great knowledge of our defensive options. Just do whatever you can to get Cloud (like Mac) offstage as quickly as possible. One thing of interest is that I once beat out Cloud's Limit Break Blade Beam by spamming Chef. I think it clanked with 3 foods at once and stopped there, but I'll have to get a friend over and lab it out. Also, Cloud has a strange fall speed like Bowser and Lucario, so make sure you pummel once or get a hit off before doing your regularly scheduled low percent combos, or he will fall out and be able to powershield it. If you can bucket 3 Blade Beams, it grants high-power bucket (43%, KO's at 15%), which is an instant stock.
As for stages, it has to do with what you're comfortable playing on. Flat stages make approaches from either character very violent. Platform stages grant Game and Watch the ability to keep away better as well as more mobility, but that just lets Cloud get away to charge Limit easier.

: I actually think, despite how broken Luma's knockback power is, that this matchup is close to even. The priority is getting rid of Luma above all else here, which, surprisingly, Game and Watch seems to accel at. Dash attack is a one-hit wonder close to the ledge, and I've found that hitting Luma with the pan of Chef immobilizes it. If you get a pan hit, spam away, because for some reason, Rosalina doesn't seem to be able to pull Luma out of it. Don't worry about a potential rush-in by Rosa, the pan hitbox is very deceptive.
Dreamland is your friend thanks to Luma being affected by Whispy, just stay away from the top platform. Batlefield, on the other hand, you should ban instantly. It mainly has to do with what stages you're comfortable playing on, since Game and Watch can do well on both flat and platform stages.

: That little dinotwerp is SO annoying. Yoshi seems to get out of everything we can throw at him with that double jump. My best advice is to play extremely patient. Hang back when Yoshi is spamming eggs, and if they run in with an aerial, rebuff them with an up smash (praise the I-frames). All in all, the hardest part is getting the KO here. Not much else to say.
Anywhere that limits Yoshi's mobility is a must. Go FD if you want to make things very one-dimensional. Beware of Dreamland and Battlefield, it's curtains if Yoshi gets you on the top platform. Smashville can be good and go Town and City only if you are good at landing Toot Toot.

: Even though Zelda is not a great character (Sakurai please), she's an absolute wall. While she wouldn't dare use Din's Fire, the fact that Phantom Slash got buffed to where we can't duck under it anymore really puts the hurt on us. Not to mention her many powerful moves (Up B kills at freaking 70 sometimes). Just be very wary of your spacing, and be extra wary of hers. Our moves have the advantage in range, however slightly, but Zelda can be more of a threat than Bowser when she starts reading your approaches. Stay patient and unpredictable.
DO NOT go to any flat stage. Like said previously, Zelda is a brick wall. Ban FD and Smashville. Town and City is very situational, but I'd stay away due to the low ceiling. Lylat and Dreamland are good counterpicks. Yes, I like Dreamland. And Lylat.

: Peach I actually don't have much of a problem with. She has MAJOR clash abuse with Game and Watch, but the problem is that Peach can't approach with float thanks to the lovely down tilt windbox. I find the most effective strategy to be a bizarre keep-away type style where instead of being defensively evasive, you must be offensively evasive. Close in on Peach, walling her with back air and forward air while stuffing her every approach with dash attack, up air, nair, down tilt, and up B. Watch for those turnips too, you can JCT (Jump Cancel Toss) a turnip into a forward air or even a hammer.
Peach's platform pressure can be scary, but at the same time if you trap her on the platforms, she can't land or pull turnips easily. I recommend Dreamland because of the wind making Peach's float go haywire. Go Lylat if you think you can get Peach offstage for a nice stage spike, as well as shelter under the platforms. If you stick to the strange keep-you-away style, FD can frustrate Peach with all of the windboxes. Duck Hunt is... well... Duck Hunt. Go there if you can outmaneuver Peach.

: This always, always, always goes sharply either way. Gyro is annoying as always, and Beep Boop and up smash are especially scary. Edgeguarding is also tricky thanks to R.O.B.'s up air and forward air, making offstage a match within itself. He can also outspace you in neutral with nair and forward air. The reward in this matchup comes with getting in close. R.O.B. is Grade A combo food, and once Game and Watch gets the grab, R.O.B. is in for major damage. The best way to tack on early damage is either the Elevator combo (down throw -> up tilt -> fullhop nair -> jump up air -> up B) or the Darth Throw combo (up throw -> double jump up air -> up B -> forward air, thanks Vader!).
I'd recommend staying away from Duck Hunt and Battlefield for obvious reasons, but Dreamland can be kind of good because Whispy shifts the Gyro with the wind. Lylat is good because R.O.B. has a high chance of sending the gyro offstage thanks to the stage tilting and allowing you to continue with your approach.
Let me know of your opinions as well, I love talking about this game.