Well 1st of all its what a Free for All? this can be very difficult because your not fighting one
person, its two and these guys can team up on you if your winning, this involves another
strategy second...Wavedash? are you saying your going to play Melee or Brawl?
because if its Melee.....im gonna walk away i wasnt good at Melee since i had no one to fight
aggaints, now if its Brawl Yoshi is much more stronger and in my opinion his Buff made his more
Adjustable and prolongs his Survival even more
i would recommen Reading a few Set up we use you can find this on a topic below this one
with the same title *Yoshi´s Set up* it may not be much but experiment with these
in your match, use whats best as for Tips on these two people
Be very Careful aggaints Fox Usmash it kills you very dang fast
Marth, watch out for counters hes going to do these a lot since its Free for all, and be careful
with his Fsmashes since it can hit you with the tip and kill you as well
overall good luck dude