"This does help, but I failed to notice (or else I fail at reading comprehension) anybody stating that the side-B is capable of cancelling Ness' up-B, leaving Ness impotent and pretty much dead. Also, Link's side-B can take someone towards you and since they are still affected by gravity, they can be drawn under the stage, making recovery nearly impossible.
If this post is redundant, sorry."
It's a beginner's guide, not an advanced guide - I didn't add any character-specific related things at all. The only times I mentioned someone other than Link was when giving an example of how a technique works (Zedging on Marth).
And the boomerang does not work like that. In order to drag them underneath the stage, Link himself would have to jump down, throw it, and jump back up. Standing on the stage and throwing it down results in no benefit. Plus, jumping out of the boomerang pull and/or doing an upb out of it is extremely easy for the opponent. Attempting to pull them under the stage is far too risky, and will do more harm than help.
I am replying via VM because the no Link mains are supposed to post on the SWF Link boards anymore (fight with the mods, long story, don't ask) and we all moved to AiB.