Question about Downgrading.

Hey Guys,
I've just ordered a second hand Macbook Pro - an Early 2011 model apparently - and want to use it for FCP 7 when on the go. The MBP is coming with Mountain Lion, which I've never used but I've heard that FCP isn't a fan of it. I currently have two Mac Mini's: One i5 with Lion installed and one old Intel Core with Snow Leopard. Is it possible for me to clone one of their HDD's with CCC, restore it to a new partition on the MBP and see if it boots with the OS the clone came from and then get rid of the Mountain Lion partition. Or do I need to get a hold of the Lion install and then follow one of the downgrading guides online - Also if you know the best one then that'd be grand.

Cheers!

From what I've read it crashes when using third party plugins. So because Apple Color no longer runs on Lion upwards, it also means the third party grading plugins I use like Color Finesse wouldnt work either.

I did some research and found that Early 2011 Macbook Pro's came with Snow Leopard and 10.6.6+ install disks with it, unless it shipped with Lion. The ebay auction says it comes with the disks, so it must've been a Snow Leopard MBP meaning I should just be able to boot from that disk, erase the partition and make a fresh one and then the install should work normally.