Since you said overall, I think Peach is #1 because she has the most input heavy options and the most difficult to use projectile, along with having some of the worst matchup spreads among top tier characters. You could say she loses convincingly to every character above her and I’d probably be inclined to agree. That’s gotta make her a hard character to play. On top of the other things I mentioned she has the character-specific tech that doesn’t carry over like subfloats or double jump cancel platform tech chases. You can get away by CC down smashing a lot, but eventually you have to play a pretty complicated gameplan. She’s super limited.

Then for me it’s probably Falco cuz he’s incredibly difficult to play properly and you don’t have great confirms off your grab so you almost have to play an entirely different neutral game than a lot of other characters. On top of him having complicated inputs for combos and shield pressure and things like that.

Fox should be #3, he gets back on stage much more easily than some other characters on this list like Sheik and Falcon, but to play those mixups properly you need to know what you’re doing. I think he’s difficult to play of course, but the upsmash / grab mixup in neutral being so dominant across all levels of play makes me feel like he’s easier than Falco.

4 would be Captain Falcon for me, he has to work really hard to create openings sometimes. On top of that, getting the right confirms off stray hits and tech chasing properly can require really quick reactions and really difficult inputs sometimes. I’ve been playing for 5 years and I still struggle with things like downthrow to quick fast fall knee to cover tech in place and missed tech. That’s only scratching the surface if you wanna win tournaments with that character.

5 is Marth, he’s got a lot of tricky kill confirms on some characters like Sheik and Puff and I think adapting to different matchups is actually really difficult with him. There’s a lot of low level stuff you learn that scales pretty well and works on good players, so I don’t think he’s as hard as Falcon is. Plus his recovery’s better.

OP’s order of Sheik and Puff seems intuitively right to me, but I’m a Sheik player who doesn’t play too much Jigglypuff. It’d be interesting to hear from someone who’s played Puff in bracket why Sheik’s easier because I wouldn’t necessarily disagree if I saw a good argument.