Yes, you can, as long the new $Cashtag you want is still available. Follow these steps:
1. Choose Profile & Settings.
2. Tap Edit Profile.
3. Input the new $Cashtag, then tap Save.
If you do this, all of Jenius users will automatically update the contact list with your new $Cashtag.
No, it cannot. $Cashtag can only be used for money transfer among Jenius users.
Activate your Jenius account immediately.
Hassle free, easy process.