A27 and Tom, I added your information. And Pommy, I added the link to the end of the first post, for anybody who wants to download.
Noidea:
1. Both Tohoshinki and Connors got the rights to that song, so technically, the song is both of theirs and neither is a cover (like how both Kumi Koda and sweetbox got the rights to 1000 no Kotoba/1000 Words and real Emotion/Real Emotion).
2. I fixed my post, just for you! XP Covers and samples are now completely separated.
3. I can't find exact information on Ayumi's song, so I'll hold off on that for now...
4. Added your two examples.
(You know, I always wondered why HOT LIMIT sounded so much like a TMR song!!
I didn't know he was the original artist. :O)