First question - why replace the calipers?  Are they working improperly in
any way?  Calipers typically last almost forever.  Generally, all you need
to do to a caliper is clean up the sliding surfaces, and the piston face.
Remember that if you do decide to replace the calipers, you will have to
bleed the brakes when you are done.

I might recommend replacing the mounting bolts and the slider bolts though.
The threads get stretched over the course of a couple/few pad changes, and
it's a good practice to replace them.  I use grade 8 hardened bolts.

Rotors come off fairly easy.  Back out the screw in the crown of the rotor
(if there is still one in there), remove the caliper and the caliper mount,
and pull the rotor off.  If it's siezed on the hub, get a bigger hammer.
If necessary, get an even bigger hammer.