SamuriHL said:1) I recommend keeping at least the update for the version you're using on the sdcard-ext just in case you have to fix it with my REINSTALL options.
2) Kind of. A locked bootloader means that anything you install has to be signed. Clearly only moto is going to do that. Beyond that, even if it's signed it doesn't guarantee you can install it. Meaning....look at the 238 downgrade to 905 issue. 905 FXZ is signed, yet, as we know you will brick hard if you try to install it on a 235+ phone. The reason for that is security. With an unlocked bootloader, you can flash anything you want. More dangerous since you need to make sure you KNOW what you're flashing is good. But you could replace the recovery partition with something a little more friendly like TWRP so you can flash anything you want. We can't do that. Nor will we ever be able to.
The update is your contingency plan. What sam says about unlocked being risky even applies to root a degree since for every person on the forums that knows how to compile a kernel and install linux without a graphical installer there are a hundred who don't even know who Linus Torvalds is.