Don't worry, Feel free to ask any question you may have
I'm not sure I fully understood your meaning. Once you install Viber on the same phone again, you should be able to activate with the code you got the previous time (meaning - no need to wait for the SMS again). So, write down the code, and use it the next time you uninstall and reinstall Viber on the same phone, and everything should be fine.
Not yet. It's currently in the works, and we hope it is ready very soon. Stay tuned for updates.