i have A LOT of experience vs Yoshi (only one, but a really good one lol).
there are few things that you need to know about yoshi:
- egg roll isn't that bad, shield it and then fsmash to the other side
- he's hard to gimp, use PK Freeze to force an airdodge, then punish, or use PK Thunder to get some damage, but cancel it fast hitting yourself or with the stage. PKT will stop him at about 80%
- he can gimp Lucas, so use all the moves you have to recover (i've been thinking and i need to work in this, specially vs MK)
- if you see a downB coming, move a little to the side and use downB and the hit with it (don't worry, lucas changes side automatically, you get a free hit and recover some %). You can also use Fsmash and reflect the stars. Usmash may work, but it's situational.
- space! Yoshi has hard time vs the pk fire, pivot grab makes his bair a bad approach (i'm loving it), his jab combo is good, it colides with yours, so this time is not that good for spacing this time, i prefer ftitl.
- talking about the grab release, rarely i get a grounded release (i don't know how) i can stop the chain with jabs. While in the air, don't try to jump, you'll lose your second jump, what you have to do is try to nair, if Yoshi is a little slow, you can use the nair, and when you cancel it, yoshi can't grab you. When you are near the edge, prepare your DI for the usmash, or if he throws you off stage, zap jump as soon as you can. Something strange his grab, is that he can't grab you while using the fsmash, i did that a couple of times yesterday, i charge the fsmash far away, he tried to grab me, but he missed (he had proper space for the grab), and i could hit him (there's video).
- i prefer dair more than nair in this match up, a simple nair can stop your cancelled nair combos :S (maybe i'm doing something wrong).
i'll say 55-45 Yoshi, i win more fight vs him because i'm in overall a better player, but i always have a hard time