I used to suck very hard against Nesses until I learned the matchup, and I have NoNessNoProblem to give all of the thanks to
(we play a lot and obviously he uses Ness)
well theres just a few things I'd like to say about the MK vs Ness matchup and this video of you playing
1. When youre in the air and trying to get back to the stage, it seems like the perfect opportunity for Ness to sit back and show you his PK thunder skills. You have to airdodge the PK thunder, it can be tough to time I realize that, since you may think you airdodged it but then you somehow get shocked by the tail...but it is possible so if you get that down, you'll find yourself with much more percentage to spare
2. If you ever find yourself PK fired, just get the heck out of there, seriously, dont try to attack or walk or fly forward, just get as far away from that **** flame as possible (lol thats an exageration of course, if you go as far away as possible, you'll explode and then respawn >_>) So if you get PK fired, you know how you just sit there and get repeatadly hit by the pillar of fire? well you can shield it and then roll out of it, or if you have enough percentage or are just high enough, you can fly away
3. this is probably just a personal preference, but I find it much easier to combo out of a dthrow rather than an uthrow
I realize this game had button lag and it was just a friendly and obviously you'd play a lot better in an offline match, so good game to you and your friend, you both played well
I hope my advice somehow helps you in the future
PS: its kind of weird that "Yoshi" plays as Ness >_> is yoshi his real main?