It helps keep your robot in the exact same place if you ever have to remove and replace the robot or if it ever becomes a little loose and you have to tighten the mounting bolts.
It takes very little extra effort to do it right so why not just do it right?
Steel dowel pins. Can you add some to the mounting plate you are attaching to the wall to locate to robot.
I'm not sure if RSR is different, but I know you can do it with PNS using multi-group UOP.
I don't know what they're plugin is, but sounds like it would work well the way you describe it.
Why not? Why can't you add some pins to your wall mount
Make sure your dip switches match this picture. All off except for 7 & 8.
Also make sure that your cable shielding is connected to the grounding clamp in the controller.
If you don't specify then it will use the currently active user frame, not world.
I suppose you could use it if you wanted to offset relative to a different frame than the one that the base point is taught in, but I have never come across that situation. Instead I just teach the base point in the frame that I want both the point and offset relative to. Then make sure you set the active uframe and utool # at the top of your program.
: UFRAME_NUM = X;
: UTOOL_NUM = Y;
On the Teach Pendent go to menu>setup>host comm>tcp/ip.
PLC guys always say it's a robot issue. 
LPOS, and Reference positions are the only way to get reliable position data without a paid option to my knowledge.
You need to use LPOS in a specific UF and UT in order for your recovery to be deterministic. Another option is DCS zones which can be sent to your PLC via DOs.
You could leave it in that position and master it to 12.3. I would only do that if I was sure that was a good reference point. Typically that isn't how someone would master a joint.
You can change the mastering angle to whatever you want on the single axis master page.
It most likely isn't a set of programs, but instead instructions for a Fanuc software option.
For vision in general, At your reference position the offset should be 0. So no need to offset.
If you are doing a touch-up at a position other than your reference you would say yes to subtract the voffset. Then it will back calculate the reference position.
I say save a backup and test it.
I believe those are programs that are part of the Initial Fanuc software install. So of course you can try to delete them after taking an image backup, but I wouldn't.
Have you tried a regular offset?
Please do not post any Fanuc manuals on the forum.
Most vision applications don't require a time output at all, so what is your actual application? Are you doing line tracking on a conveyor? If so Fanuc sells a line tracking vision option.
Why are you needing this? What is your application? There could be a different method to achieve what you want.
