Creating a "custom" Caladbolg
Unfortunately not.
Celestial weapons have a unique name and appearance. They also have unique abilities in addition to the 4 displayed - usually relating to aeons' damage limits. Caladbolg doesn't affect any aeons but it does have a slightly different damage formula that causes Tidus to deal more damage when his HP is higher.
The custom Caladbolg would have the abilities you put on it but would have the appearance and name of Excalibur (from Break Damage Limit) and would use the standard damage formula instead of Caladbolg's.