Aight here's what I think:
Approaching: Bair is pretty awesome, a lot of hitboxes so it's harder to punish, can do a pretty good amount of damage, and if you catch them in it you can end it with a U-air or jump U-air depending on how they DI and continue the combo. Fair isn't bad also, if you keep your space and fastfall L-cancel. Plus this is a great combo started, and if they try to jump and do something the hitbox covers a lot. DJC Nairs are good if they are unexpected, like jumping away then double jumping to turn around and send you momentum back towards them, but sucks if you get hit out of it haha (like all his aerials I guess). Spaced D-tilts are good and have great range. And if they are on a platform above you I love doing the jump canceled running upsmash to get my head under them.
OoS: Nothing. haha nah but not much. On platforms obviously shield dropping is a pretty good way to get away from pressure (or U-tilt out of it and it can be offensive). Light shield can slide you away from pressure. My favorite is D-smash (usually spot dodge D-smash). D-smash comes out really fast and if you can spot dodge their attack and throw it out fast it usually hits (and can kill pretty easily). More advanced methods would be like jump cancelled parrying (which would keep you from getting stuck in your shield but would require a lot more precise timing then just holding shield haha) that's all I can think of for now