Yoshi is super hard, good character is good.
https://www.youtube.com/watch?v=WpzmzpZqY00#t=492
This is an old match, from the first smash 4 Tourney we had in AZ but I won with GW while my Rosie was losing. You can still probably grab some useful matchup info from it. I actually play against Yoshi a lot but I go Ness and Sheik on him so I don't have any real info for the specific matchups
however the secret to beating Yoshi is NOT BEING GREEDY
It deserves caps lock. Yoshi has the strongest combo breaker game in this game and if you extend too much he will reverse the momentum in a very powerful fashion and you WILL lose, because Yoshi's DPS is crazy.
Get your hit and reset, You'll have to keep beating him in neutral but you're not going to beat his Damage output so don't try. The flinch armor on the double jump, the nair, and the Up-B will save him from a lot of stuff. Even the down-b if you try to extend too much when he's above you and it WILL KO
Trust me, once i figured out why I kept losing to Yoshi and started playing less committal with my combos/strings it was loads easier, and as a GW main you should have pretty decent neutral anyway because he's never had free ways to approach his opponent (Except Bair vs low tiers in Brawl, but it didnt work against good characters generally)