Okay I'm bored so I'll do my write up. We have two PR Yoshis here in Michigan, so I get decent practice in this matchup. They both play a little differently as well, so I have experience against several playstyles.
Something to note is Yoshi likes to spend a lot of time in the air. Yes, he may occasionally back off and throw eggs but our shurikens (especially when we get that magic short hop height that we can clip his head with them if he stays grounded OR catch his jump) are basically going to put the onus on him to approach in the matchup, and Yoshi generally approaches from the air. This is fantastic for us, but we have to abuse it correctly. Up smash is such an amazing tool in this matchup, and if the Yoshi you're playing is overly aggressive you can seriously just run under them as they're trying to land and up smash when they run out of options. Nair is also amazing for covering Yoshi landings, as well as pivot smashes and grabs. I believe when it comes to the neutral, we win this matchup.
When it comes to edge guarding things get a little hairy. Yoshi's fair is incredible offstage and I highly suggest you be incredibly careful when going up against it (read: don't go offstage). Against a Yoshi with rage I have been hit low enough where I was unable to recover at 40%. This means very sparingly should you be shadow sneaking to the ledge, and you should be mixing up your recovery to stay as far from Yoshi as possible. A Yoshi that knows the matchup can trade his fair with shadow sneak and spike you every time.
The good news is, however, we don't have to go offstage against Yoshi to edge guard him. Yoshi REALLY struggles to grab the ledge, and most Yoshis will just use their heavy armor jump to power past the ledge while usually taking not much more than minor damage. We, however, have two very fast, disjointed, and powerful smash attacks that can hit him for devastating effect regardless of how he chooses to come onto the stage. If the Yoshi is trying to egg and snap the ledge, f smash breaks his eggs and smacks him out into the blast zone, hopefully for him he saved his jump! I find walking away from the ledge is a good way to bait this. If he tries to super armor jump, up smash covers it really well if you time it right. Just be careful that if you do it too early Yoshi will be able to armor through hit one and nair you before you can get hit two out. Annoying. If Yoshi is choosing to ignore both of these options and recover high, hydro pump can really screw with his momentum and cause him to do unsafe things (if you can catch a down b with hydro pump, oh man is it hilarious). Offstage play Yoshi dominates, but edge guarding is even or maybe in our favor. Another option to consider! Yoshi can double jump past the ledge and neutral b you if you're too close. This puts you offstage and in great danger of death at high %. Learning how to mash out of the egg and avoid a potential f-air is good, but it's better just to avoid this situation entirely.
Yoshi is somewhat annoying to combo, but the good news his he isn't really able to armor jump out of up air unless you barely have him in the hitbox. So our combos work pretty well on him. Just be careful about overextending, down B will kill you super early if you go for greedy up airs. We are a delight for Yoshi to combo too, but a little more awkward than the other fast fallers. Just be aware of f-air in neutral and its ability to pop you up if you don't block it or miss the tech. You must also be aware of his jab setups, do not give him an air dodge and do not block for too long (down b will break your shield). If you mash jump Yoshi shouldn't be able to kill you with anything guaranteed. Yoshi's main combo starters on us are jab 1, up tilt, fast fall aerials (especially up air, fair), and egg lay.
Okay so I think that covers a lot of the matchup. Just be patient and punish his landings, then cover his attempt to get past the ledge and you have a good shot at victory. We have a lot of things Yoshi hates: range, mobility especially. Remember to make them count.
I think this matchup still is even, but has the potential to be as good as 55:45 Greninja favor.
Oh right, stages.
Stages to go to: Game 1 get rid of Lylat and Battlefield. Doesn't matter where else you end up. For your counterpick go either T&C or Duck Hunt, the latter is especially good against Yoshi. The tree and walled edges make recovery for Yoshi really awkward, and the lack of platforms gives him very few landing options against our up smash. T&C is more even, but I feel with our setups killing off the top favors us a little more. Inconsistent platforms also make life annoying for Yoshi.
Stages to avoid: Here is the thing about Yoshi - Duck Hunt may be the only stage he kind of sucks on. So when banning, ban what you feel most comfortable with because Yoshi has 3 amazing stages and he will take you to one of them: BF, DL, or Lylat. If DL is banned in your region you still have to take a 50:50 on what the Yoshi prefers but I will tell you what I ban every time right now:
Lylat is a nightmare against Yoshi. Shuriken camping is hard, landing safely is nearly impossible (up smash through platform), and the annoying edges and blastzones just amplify Yoshi's offstage game. It's basically like the flipside of Duck Hunt for us. Unless you feel INCREDIBLY comfy with Lylat I'd flag this as maybe the worst stage in the matchup. Battlefield is more doable, Yoshi loves the platforms and his offstage game is still really good because of the huge blast zones, but our combo game works well here and we can edge guard him pretty effectively as well. Dream Land is best case scenario, we get the low ceiling mixed in with the better platform height, but most Yoshis don't seem to prefer it over BF.
Ok I think that's it for real this time.