as for peach holding a bomb or stitchface, DON'T use your second jump or your air dodge, a good peach player will be waiting for that second jump to come out, and at the last second if she knows you arent going to air dodge (and at that point it would basically be a wavedash unless you airdodge up, which i wouldnt recommend either in case she hesitates), it'll be an easy hit on you. i'm very good at spot-dodging items (although i never play with them), so i try to get inside as quickly as possible, if you rack up some damage on her she'll throw it at you in desperation (she has to throw it before she gets in danger of dying, that would be a big waste), and you should be able to easily dodge it.
As for a jumping fox, DESTROY him with fair combos, leading up to either a spike/ken combo or L-cancel to Fsmash. If the Fair his him just as he is landing, L-cancel to grab, uthrow, utilt, fairs, etc.