Again, it's the same thing will ALL of the comparisons you've made -- and you've made a bunch. All that such comparisons can prove is that "Jason Malachi, on this particular song, in this particular part, sounds a lot like Michael Jackson, on this particular song, in this particular part".
Keep in mind I don't know whether the Cascio tracks are real or false. But such comparisons cannot, by their very nature, provide proof one way or another.
Here's a way I can explain this : suppose I produced a .wav file of myself singing, say, a part of "Privacy", where I managed to sound almost exactly like MJ on some parts of that song. Would this file prove that I am the one who actually sang "Privacy" on Invincible? Of course not.
The only way this debate can finally be laid to rest one way or another is if other kinds of proof are provided, and in particular, if this question can finally be answered : How could such a hoax be pulled off, considering the number of people who would have to now hold their tongues for the rest of their lives?