Ah yes, this matchup is very interesting to say the least. Uncle Bob (Mii Swordfighter) is one of my main characters, so I can share a lot of input about the matchup.
The main things Charizard needs to look out for are his early combos, dair (has a gimp spike), bair, usmash, Uair, and believe it or not, Uncle Bob has a hoo-hah (
). Being that Mii Swordfighter doesn't have a guaranteed kill setups, Charizard can take advantage with his heavy weight and last until he's around 160% or higher. If you play the matchup patiently, you should be fine against Uncle Bob (Mii Swordfighter) and for the love of God, don't get hoo-hah'd...
Now I only play the 1111 version, so I can provide some input on what Charizard should be doing against Swordfighter.
Neutral
Putting out your flamethrower can shut Mii Swordfighter's option in trying on grab you and in general, due to its poor range. However Mii Swordfighter can jump over the flames and do a falling uair to grab/utilt for days. It is best to throw out some empty nairs or empty hops to force Swordfighter to come at you. All of Mii Swordfighter's specials are useless in close combat and even far away (except for the gust of wind). It's best to dash shield towards Mii Swordfighter, since he'll most likely do some retreating fair and nairs to space themselves out. Fighting Mii Swordfighter is like fighting Link, only Mii Swordfighter doesn't really have projectiles, so take advantage of his low range moves.
Mii Swordfighter's Hoo-Hah
Mii Swordfighter can deal around 21% (I believe) from a dthrow to uair. The way you get around it is to mix up your DI. Either DI straight up, or DI diagonally away from the character. It is a true combo in the early percentages (up to 40%). If your above 40% and they do it again, your best option is to quickly jump away from Swordfighter to avoid any free damage.
Edgeguard
Once Mii Swordfighter is offstage, they will most likely save their second jump to be able to jump closer to the stage and up B. If you see Swordfighter using the side B (forgot what it's called), let the character hit you and it intercepts them from traveling any further and they go into their free fall animation into their doom. I would only recommend going out there if you feel Swordfigthter has no where to land. Don't be afraid to go offstage and try to Dair spike Swordfighter. Although if they are recovering high where Charizard is unable to chase them in the air, go for a flare blitz the second they land.
Utilt
Don't bother trying to challenge it. It comes out so quick that if you get caught in the utilt, you'll be taking so much free damage anywhere from 0-42%. Once you get caught in the utilt, it's best to DI away or jump. However they could mix up the timing rhythm by not using the utilt for a split second, and then Charizard falls straight into their grab range and get hoo-hah into oblivion. If you get antsy for a dash grab and they side dodge, thats usually their way of asking Charizard to be up tilted all day.
Catching their landing
Swordfighter has some options on how they could mix it up. Uncle Bob (Mii Swordfighter) can put up the counter if he anticipates an usmash. Also, they could try to tomohawk grab to pull off the hoo-hah, so it's best to either fly or rock smash. Sometimes you'll see them trying to space themselves with a fair to grab/jab (if spaced properly). The best option against Swordfighter is run beneath them and put up your shield until they get close to you, or if you can shield grab.
Dair
When your returning back on stage, they usually will dive down deep and dair spike you. What you can do is use fly before the animation comes out and you should be able to return back on stage safely, thanks Charizard's super armor. Be aware that on stage they will use the rising dair out of shield, so be wary of that. When the dair move lands on stage, it creates an earthquake shock, but it doesn't autocancel, so take advantage of its high cool down lag. Every once a while, you'll see Uncle Bob (Mii Swordfighter) come down with a Dair to cover themselves, thanks to the long lasting hit box. Good thing to take note that Charizard's uair, usmash, and utilt can actually beat Swordfighters falling dair.
Stage Counterpick
Mii Swordfighter doesn't really gain any benefits, due to lack of kill power, no good projectiles, and average in just about everything. Because Miiswordfighter has no kill throws, you can get away with taking them to smaller blast zones.
If you play really patient and not get yourself caught into Uncle Bob's (Mii Swordfighter) early combos you should be fine. Remember to put up your shield a lot and you can punish their attacks accordingly.
Matchup Ratio:
65-35
Charizards favor