Using different style disc rotors with the same brake calipers
You've gotta try it out to some extent (e.g. at your LBS). But you'll likely be able to do it with some spacers, tweaking of the brakes and some fidgeting and appropriate part selection. If you do it right, you should have minimal/no adjustment between swapping the wheelsets.

It depends on the brakes and rotors you have. In some cases, the rotor will fit fine or need a minor adjustment in pad placement, while in other cases you won't get the rotor to be able to align properly or the rotor will be too wide and maybe have suboptimal braking (e.g. excessive pad wear or reduced braking power). You may be buying a Centerlock->6 bolt rotor adapter depending on the rotors you're planning to run or some spacers or something to get this to work.