They’ll work totally fine. All rotors work with all brakes. Simple.
Not strictly true, avoid using Avid Juicys with any rotor with an aluminium carrier (Hope floating, shimano XT etc.) as the rotors foul on the pad removal tabs.
popps, X2 brakes and C/L disks should be fine, however as stated above you may need to realign the caliper. Or, you could be lucky as in mikewsmith’s case. Only one way to find out…..