[ghettofreeryder]

1) Yes, tweak to your liking. Add, remove, modify, etc
2) You can either convert the cab to an oem, or add the cab to oemapps, and call it in config_x.txt in the carrier folder
3) Add the registry tweaks to the registry tweaks provxml
4)To remove the email tab, you must remove the tab calls from the manila xml config file. Do some searches over at xda