I am installing my new JVC kw-r910bt aftermarket stereo, and I'm also wiring the harness, so my question is can I use 16-14 butt connectors to wire the harness?
Yes, that is a very common use for those connectors. Use the correct size for the wires you are joining. You may still wish to wrap the connectors and excess wire with electrical tape, when you are done to keep things tidy.
You can, but I solder all my wires after checking for proper operation, then insulate with shrink tube.
Yep, you absolutely can. 14 awg is a little too large for a head unit installation. I would highly recommend using 18 awg.
Could use bullet/socket connectors for easier changeover of head unit.
