#1
If I had my guitar set up, and I change the strings (using the exact same size and brand) and I make sure the saddles don't move, then it will retain perfect intonation(or however perfect it was before I change them)?
Telecaster - SG - Jaguar
Princeton Reverb, Extra Reverb
P-Bass - Mustang Bass
Apogee Duet 2 - Ableton Suite
#2
Chances are your intonation will be nudged if your bridge saddles move, which they may do slightly anyway. But they won't move by much. Shouldn't take you more than 5 mins to check, 10 if they have slightly de-intonated. Try it and find out!

Rob

Ibanez S470
Laney HCM30R
Digitech GNX3000