Based on the dimensions you've provided, you could probably just squeeze a 345 in your wheelwell. A 13.625" section width and 14.56" wheel opening width pencils out with just under a 1/2" of clearance per side.
Keep in mind that the tire section width will vary depending on the width wheel you use. Also, wheels are generally 1" wider than their bead to bead measuremnt, so a 12" wide wheel actually measures closer to 13" from the outside of the lip to the other lip. As for brake fitment, the rotor hat thickness you've shown of .100" is thin, much more similar to a drum hat thickness than most rotors. If you know which brakes you are planning on going with, post up so that someone can tell you exactly what the rotor hat thickness will be. FWIW, C5/C6 rear rotors are .24" thick and C6 Z51/Z06rear rotors are .28". Caliper clearance is a function of the amount of axial and radial space around the caliper relative to the wheel mounting surface, typically the outside of the rotor hat in a disc application. Take a look at the fitment templates available for download
here as that should answer your questions concerning caliper to wheel fitment.
Tobin
KORE3