On the contrary, Kewl why should you ever approach those characters *barring DDD*? You can camp THEM on FD.
With realistically 2 jumps, Up B, and U air and an awesome floaty parachute, G&W should never be hit by a Nade, and flies all around they stage just poking Snake. Yes its hard to get Snake in a juggling position, but its also hard for Snake to touch you. FD gives you more options to approach with.
DDD can't approach for the life of him, when you can D tilt his projectile and keep in the air for his F tilt. And your best approach is coming from about and the side and FF bair and get out of there before he can f tilt you. If you try and SH Bair him he can F tilt right threw it. You cannot do this on BF and he can shield and Nair, Bair, or U tilt you after if you try to Dair or D smash.
MK ***** on BF. U tilt and U smash go through play forms, and your Dair. You get *****, and all he has to do if stay on the ground and be patient. I've played Havok a lot. This is all he has to do to win.
Your best bet against Marth is FD. he's tall, yes, so you can use BF. But SH Bair approach gets ***** But shielding + Dancing blade. Miss-spaced Bair gets ***** by Up B. Smart Marths can bair you to try and Dair them through the platform, duck, and tipper F smash you. FD just gives you more room to breath, and doesn't make it a real pain to get back on the ground. Which is the safest place.
Where's my cookie?
G&W players. Stop approaching. Think. Punish. Patience. D tilt.