In my limited experience, IMDb is what middle school teachers always told me Wikipedia was like. I honestly cannot for one second buy that "Be Prepared" would've been cut because of the Nazi imagery, especially since they still air this movie unedited on Freeform and other Disney channels and I've never seen anybody bring it up online as a criticism (expect maybe once to say that it's a little extra and goofy).
And Chiwetel Ejiofor has a decent singing voice;
Kinky Boots and that scene from
12 Years a Slave (
https://www.youtube.com/watch?v=mAZhQQN758g) are enough to convince me that he could at least carry the song well. Not to mention that Jeremy Irons talk-sang/snarled his way through much of his rendition of "Be Prepared" anyway; it's more the attitude than singing ability that makes the song work.
Edit: Speaking of whom, some of my friends back in college just met him today, it seems.