mobile

So my device is currently with Telstra and they are real slack with their update releases and tend to have a fair bit of bloatware on their devices.

I obviously have the xperia z3 compact and really want to put the official android 5 release on it.

I have a few questions/statements down below:
1. Can I install the software without unlocking the bootloader?
2. I don't want to loose camera functionality or DRM keys (just don't want faults or bugs like this.). - Anymore info on this?
3. Can I just root to install the software?
4. Is there anyway what so ever that is safe, where I can install the official Version without a carrier? (Australian Radio)