Default Lock homescreen + change default apk icons for sys apps

its probably possible to edit the icons of system app icons except i cant seem to source any information through google around to what tool/method is required. the 4.3 tw default icons are ugly as hell compared to cm.

other question is did the 4.3 tw based roms not have the ability to lock the homescreen from accidental modifications or am i just mistaking that coming from asop. i swear i saw the option before but i could be wrong.