1. I already pointed this out, but I guess you don't read well either, but you said side-b. Side-b consist of both the kick and the flip so I'm only going to naturally assume you're talking about both, if you're not then say flip or kick.
2. I already said this too, I swear you only browse through what I post and don't read the details...If the MK does it right then the only way to avoid the tornado is to drop down and then grab onto the ledge again which still puts you at a disadvantage because he should already be out of the lag from the tornado unless you have a banana in your hand.
3. The grab only goes through the tornado if he's close to the edge where it's in the very beginning of the nado, also it has to be spaced right. MK shouldn't be nadoing you when he's close to the edge anyway though.
4. Yes, when you properly predict something you can punish everything, but he has a much greater chance of hitting you anyway because of his options. The reasoning is that so many of his moves cover multiple options you have meaning he doesn't have to predict as well giving him the edge, getting punished near the ledge with MK is very very bad, especially if you don't have a mid air jump (which you have to use for the side-b)