Anyone? He's coming over tomorrow to practice and I want to give him all the advice I can.
He seems to favor hard reads (charging f-smashes with ample room to dodge, for example) which can lead to big problems against good opponents. He also rolls quite a bit when walking or running will do. I'm not sure if it's the nerves getting to him, but ideally he needs to relax and take his time. He has more options from a standing or walking position than while committed to an action. Save the smashes for when they are more of a sure kill, and mix some tilts since they have good power and speed. In most of the matches I watched, tilts were almost ever used and would have been a far more ideal way to punish or set up some combos than all the f-smashes being thrown.
Watch out for Bowser's shell during any attacks that use it, as it has some wicked priority. It's better to attack around it than challenge it.
DeDeDe's tilts and smashes have better range than Ike, but all except F-smash and f-air have limited arcs. When approaching, come at a diagonal to maximize Ike's effectiveness.
Charizard is big, making grabs and tilts extremely effective. Also, throw a counter in once in a while as Fire Blitz are a death sentence for Big C with the distance he was cracking them off. Rock Smash give Charizard some super armor during the smashing parts, so it's ideal to either avoid or go around and b-air from behind than directly challenge.
When chasing after a fleeing opponent that is rolling, he'll want to run a little farther before using his dash attack or a grab. Aim the strike where they will be and not where they were. It's a common mistake that many of us make starting out. It's all part of reading your target.
When going for the Eruption, get closer to the edge as he'll want the most of the blast as possible to penetrate through the stage (and may get lucky with the tip's spike). Eruption works best against the deep recoveries since the only option the opponent has is to sweetspot the ledge, meaning no punishes heading Ike's way.
During recovery, he'll want to try to aim for the sweetspot with the Aether than landing on the platform when his opponent is a good rolls distance away as the landing lag is severe enough that Ike will get sent right back off stage after.
Hope some of this helps. Let us know how the friendlies went!