I don't know how well you know the technicalities of chiptunes and console soundchips uzo, but nothing posted has been an upmix in the sense you're making it. Easy routes, surely, but certainly nothing deserving of you treating Chern's entry like a pariah.
Converting Aria's songs into SCVIV's style only counts as an upmix on extremely mundane levels of what each console could support. Due to the GBA being a tiny handheld, it should be expected that it has less processing power than a console five times its size. So in that regard and that regard alone you're correct.
And what part of "he did the entire soundtrack" are you conveniently forgetting? He's done a good deal of work, which for someone known not to do chiptunes, samples, or soundfonts is a display of skill. Am I saying his Aria entry is perfect? No (could have done with a little bit more release time on the samples, Chern), but for being entirely out of his usual playing field I think he's done a fine job. But I'm not a judge, so what do I know, right?
Yes, converting HoD is an even easier route, since it reused a lot of CVIII's samples and styles, but it falls under the demands of the contest. Even I have to facepalm a little at it, but that's only because sampletunes and chiptunes are a practiced specialty of mine. Chern doesn't do it, so of course he's going to take paths of lesser resistance. It's not a lack of skill on his part, it's a safe play. He doesn't know the full technical ramifications that go with the territory of chiptunes, and it's not really something you can just up and get the swing of in a month. Expecting a "standout" entry from him is unfair of you, because you know this area isn't his forte. If he had more experience in chiptunes I have no doubt he'd be putting forth Emmy-nominated songs, but that's not the case.
Your opinion is not law. Are his entries upmixes? On a purely technical level, and a minute one at that, yes. But they sound good and fit the style adequately for him being out of his element.
Lose the attitude. I knew what to expect going in with this theme, so calling it "my baby now" is irrelevant. It was my baby from the start; you can't dump something you don't like on my lap like it's going to shame me or something. Save your snark and snide for after more entries get in.