The competitive SSBM discussion thread

Also, how do you (khoi) edge guard with jigglypuff? Sing guard? Edge hogging?

Fair/Bair is usually the way to go. Dair is meaningless. Nair has no knockback. Uair sends them up so they can recover with DI more easily. Forward B will knock them towards the stage if you use to away from the stage; i.e. Forward B pushes people behind you. Last I recall anyways.
Sing is pretty useless in both versions, I would say. I've seen maybe two Sings in competitive play in person (that wasn't stalling death from falling). They were both just completely random things that caught someone off of a tech.
Edgehogging in Brawl is more difficult but it depends on the character you're defending. Brawl+ doesn't have auto-sweetspot from what I know, so edge-guarding with a Forward Smash would probably be the easiest choice against most people.

How am i supposed to incorporate grabs into a rest combo in this game? I don't know how hard it was in melee (apparently it was way easier), or if it's the same way in brawl+ compared to brawl.

I have no idea in Brawl, but if you're playing Jiggles, in Melee, you could Down Throw -> Jump + Rest on a Space Aminal at less than 40%. Otherwise, people usually Down/Forward/Back throw, and then follow up with a SH(FFL) Fair/Bair or two.

I believe it is considerably harder in Brawl because the grab mechanics are very different for a lot of characters compared to what people were used to, as well as what characters have in terms of recovery. A lot of recovery times in Brawl didn't originally allow for attacks to be "Comboed", and Brawl+ helped fix that.
I'll have to find a Wii and pick up a Brawl disc from somewhere to look into this though, specifically for Jiggles too. Never been much of a puff fan, except when I'm playing some scrubs and just WoP them off the edge.

@Goals: First thing I would recommend you do is get a feel for your character's attacks. Understand their reach, speed, and knockback. For example, as I said up above, Jigglypuff's Forward B knocks characters behind her, so you should have a grasp of when to use it now.
A lot of moves can be useful, but a lot can be worthless as well, though some are arguably opinion. Toss up some characters you want to play as and we should be able to give tips.