With Fox, Ike has to be careful when in the air. Fox thrives against aerial targets since a lot of his moves have little ending lag, so you'll want to minimize some of your airtime. If you get caught in a combo, keeping calm and using DI will help save you. An extension of this is to watch for his grabs, since they hit decent but more because they'll get you airborne. Not much I can say to prevent this except that your jab is about as fast as most of his moves, so don't be afraid to use it on a grab-happy Fox.
With edge guarding, I feel that baiting his recoveries and countering would have been more effective than Eruption. Eruption is still useful against his Up-B when recovering low (especially if he knows how to sweet spot the edge), but when approaching from the side Counter can easily caught his Side-B and Up-B. If he's anticipating that, which a few times in the beginning he was, he'll try to be closer to you so the end of his Side-B zips out of your range. Perfect Shielding it, then grabbing him and throwing back off the ledge is a good strategy to keep him in a slight panic. (Started doing this in the last 2 fights, which is why he started mixing up his approach during recovery)
You'll want to study his range and speed more, as you had some great opportunities to punish him on whiffs but had a hard time landing them because he had a better understanding of how your range for different moves worked compared to his speed. ( I think you saw some of what I'm talking about to, as you're play style adapted later on to anticipate this more.) I feel with this, practice is your best tactic.
Lastly, watch out for repeated edge grabs without touching the ground. If I'm remembering this right, you're invulnerability is only for the first grab. He saw that you had a pattern with juggling Aethers from the edge and eventually punished you for it. It's a cool move, and catches quite a few by surprise but gets predictable easily (plus with the slow wind up can be easily punished once they start to predict it). A rising N-air could possibly be something to mix into your edge fighting, or if you want to get fancy a rising Counter if you expect him to try to punish.
I will say one last thing though, and that is to not be afraid of his lasers. I'm not saying that dodging them isn't a good idea, but since they don't have any knockback and he has to put his blaster away before doing any actions you can get close fairly easily for some beatdowns. Staying back a little to make him think you're afraid of his blaster, and then rushing up and smacking him around is a good way to catch a fox player by surprise since his timing will be based on your defense. He needs you at a higher % to kill than you need, so if you've got him at a good % chancing the lasers for the surprise can be a good way to make him scared to use it for racking up damage.
I think you were a lot closer to your opponent in skill then you believe, which is why most of your matches were so close. I know it's a wall of text, but it's all smaller stuff that I fear needs more details than just saying "Watch the air and mixup the recoveries". Hope it helps.