I'd normalize the audio track in 2001: A Space Odyssey. Dynamic range is great, but I shouldn't have to ride my home theater's volume knob like a roller coaster just to keep from pissing off the neighbors at night.
Eh, I dunno. They both use the same song (which is no sin on its own, mind) but I think if you wanna say they're edited similarly then that would come largely from the fact that the language of editing, particularly for music videos, only has a limited number of ways of coming together. They both need to visually express the fast paced, mashup nature of the song while also keeping the source videos visually coherent and recognizable as they transition in and out.
In fact, I think there are more differences between the two than similarities. Fan.tasia uses a lot more complicated compositing, transitions by using moving elements in one clip to cover wipes to the next, and really likes the whole "pull out from the iris" thing where Imagine prefers a lot of quick cuts and fades. Between the two, I think Fan.tasia is superior from a technical sense.
The only thing I could say is inspired by Imagine was the credits section at the end which, even then, was done better. But really, since when has inspiration required credit? It's far from a rip-off and it's not like Fan.tasia recreated Imagine shot for shot.
It should also be noted that there are a wide range of options available under Creative Commons licenses through sites like Jamendo, CCMixter, FreeMusicArchive, Incompetech, and even SoundCloud. These do require a little more due diligence on your part, however, as I have personally found it to be the case that an artist might put their music up without fully understanding what Creative Commons licenses entail (specifically the clause which makes them irrevocable). You may also run into the case where an artist has placed their music on those sites, but they were later pick up by a publisher/label who has logged the songs on YouTube's Content ID system. This has created the situation for me on a couple of occasions where I had the right to use a song in a commercial video due to the CC license put on it, but the publisher/label flagegd/monetized my video and refused to play ball and restore my monetization.