Question [Q] About Unlocking, Flashing and Rooting

Hi, I am new to XDA and this is my first ever post, so Devs, be easy on me.
I own a Sony Xperia SP device (c5302) which is currently running Android 4.3 (12.1.A.1.201) and I want to gain root access on my device.

I looked at several tutorials and videos and found that I need to have the Bootloader unlocked first of all. I am not sure about the exact procedure as every tutorial follows a slightly differently process.

Here are my questions as a newbie.
  1. I want to know that what losses can I have if I try to unlock my bootloader?
  2. After rooting, will I be able to get the same android and build version running on my device i.e. Android 4.3 and build 12.1.A.1.201?
  3. Will I be able to get future updates from Sony that are shown in the phone as notifications as and when the updates arrive?
  4. Is it possible to bring my phone back to the same condition it is in today? Like it was never rooted or the bootloader was never unlocked, because I want to avail warranty as well?