go back to the kindergarden.
Learn to communicate without flaming.
Take a Samus. Take a Fox. Go to FD. Mash AA on Fox 'til he's at 68%. Place Fox in the center of FD. Shoot him with a fully charged Charge Shot. Watch him die.
Kill Samus to reset the damage reduction on her. Repeat the above process, except that this time, hold up on the analog stick before shooting Fox. Watch his trajectory curve significantly higher, and he survives (just barely.)
Kill Samus once more, repeat the process, except this time use C-Stick Up. You'll get the same results as the first time (a straighter path, and a KO.)
Moreover, when you shoot Fox with a Charge Shot, if you rotate the Analog Stick rapidly, you'll notice that Fox jerks around rapidly during the hit lag before he actually gets sent flying (i.e. you Smash DI the attack multiple times.) Try that with the C-Stick, and you get nothing.
Moreover, I highly doubt the C-Stick does anything for your roll distance. Regardless, at the very least it does nothing for DI on its own. Unless it has some magical property where it enhances the Analog Stick's effect on DI, Double-Sticking seems like a hoax.
And by the way, Crouch Cancel is NOT DI. Crouch Cancel is taking a hit while crouched, which makes it have significantly less knockback. If you continue to hold down as you're hit, you'll do an Automatic DI downwards. However, it's possible to take a hit crouched yet DI in another direction, and it's possible to take a hit standing, and DI downwards when you're hit, without having CC'd the hit. Moreover, you MUST be crouching to Crouch Cancel, so you're obviously not CC'ing the bomb, you're just Auto DI'ing it downwards.
Just because you can do both things together doesn't mean they're the same thing. Regardless, this isn't the thread for this discussion. Let's try to keep this on-topic and focus on Brawl.