Batman, true.
Harry potter, yeah while he could kick the crap outta a ton of these guys, if a pipe bomb can blow him up, he wouldn't stand a chance against the more metallic characters. Which in a way makes it so people like Terminator and Robocop could beat him, all they need is explosives since they are invulnerable to them.
Mister Rogers, maybe if he had that sword but he'd have to steal it from someone since he wouldn't come in with one and after everyone knowing about his victorious video. They'd go for him right off the bat.
Another suggestion of a warrior to throw in is Ditto from Pokemon, simply because it's pretty tough to beat something that actually can become your 100% perfect duplicate in every way.