From what I've read, if they couldn't match Freddie's voice to the image they used the Canadian singer Mark Martel. He's the singer on the official Queen Extravaganza touring show. He's pretty good. I think Rami's voice was used only when he sang up close in the studio or in the alley audition, something like that.
https://www.youtube.com/watch?v=ptr3..._ibZu&index=37
https://www.youtube.com/watch?v=egtJi967tgM
https://en.wikipedia.org/wiki/Marc_Martel