Yes, that all can be done. But my big advise is for you to let a Pro do all that wiring for you. Ford's stock setup is a little complicated and not simple at all. And yes, definitely change the Head Unit. Again, let a Pro do it. Understand, I am a Audio file and do have some knowledge on stuff, but even I know that sometimes it's better to let the Pro's do it.
07 GT. PREMIUM SCT: CUSTOM TUNE by "MUSTANG SPECIALTIES". FULL MAGNAFLOW COMPITION EXHAUST, LT. HEADERS AND X PIPE, LMR: GEN2 2010 STYLE HEADLIGHTS, RAXIOM: 2010 SMOKED COYOTE TAIL LIGHTS, WHEELS: STAGGERED WHL 22X8.5F-22X10R MORE LISTED INSIDE.