Yes centre lock and 6-bolt are compatible with all calipers.
Brake discs can only lose heat through radiation or conduction. Different materials do both at different rates but since most discs brakes are made from stainless steel (of more or less the same heat radiation and conduction), there will be no difference in terms of heat loss through radiation. And, since the paths of conduction (the contact area with the hub) are the same, ditto for that.
Therefore, on the issue of heat dissipation, they're all the same.
Now, why do you care? Are your current discs not good enough in this area? You'll know, because they'll stink, fade quickly and show the tell-tale blue tinge on the inner edges.
The type of pad has more of an effect than the working temparature of the disck. Resin pads will run quieter and perform better at lower temperatures and, the opposite for syntered metal discs which perform poorly at lower temperatures and are noisy. The latter is good for downhill/enduro applications and the former for commuting.
My guess is that you don't need a new wheel upgrade and even if you do so 'cause you just want new wheels, there's no need to consider the cost of the disc as it has no bearing on performance.
Morfe of a consideration is whether or not you'll be swapping wheels from time to time. In that case, make sure both discs are compatible with the type of brake pads you're using. Low-end discs cannot be used with syntered pads.
This gets so complicated and techical, that it is best to just go for a ride and drink a beer and forget about upgrades. It's mostly nonsence.
