I don't have many problems with Pac Man, like most mid tier characters, he has no real reliable kill moves while Falcon has like 4. But due to how rare it is to actually fight a pac man, the matchup is hard to grasp.
But basically just knock his hydrant into him and fight him like any other character at that point. If he trampolines off the stage, run off and take his 3rd bounce, you'll recover no sweat and he'll fall to his death. Just remember his dash attack is really really good, but his grab is easily the worst in the game due to how obscenely laggy it is. Once you hear the boss galiga tractor beam sound, you can just rush him as his grab wont work anymore at that point, but he still has like 40-60 frames to go before he can do anything else.
Just be weary of the Bell, Melon, and Key projectiles, those ones are pretty nasty.
ZSS... Yeah I'm lucky(or unlucky) and don't fight those very often. jab/dash kills their B, and you have a way better ground game then them, just don't try to contest the air too much.