So, with your first idea, I love it!!!
Having beaten TP multiple times, I know more or less that the chances that you mentioned are actually fairly accurate, so I'll use those percentages(And credit you, of course); thanks!
The second idea, though, I thought about it, but in the game, the only time he ever actually does the grabbing-on bit, though, is when it's a really giant character, like the Twilit Bloat, or a Kargarok, for example, and the only characters that are really that big are King Dedede and Bowser, and it wouldn't really be balanced if he could stun-lock only those two characters and nobody else. That, and stun-locking from an instantaneous charge-move is also kind of unbalanced. I do like a lot of your ideas, though, and they are well-thought-out.
actually he does do it to some higher level normal enemies like redead knights[or are they gibdos?..i honestly never knew]