I'm finishing my router table extension for my table saw, and seek advice about the following:
My saw is a Grizzly G05444Z with a standard rail. Thus, the table is 27" wide and approximately 18" deep. See images below.
1) Any advantages to a separate fence as opposed to clamping an accessory fence to existing rip fence? Either will have to be removed for wide stock ripping.
I think that depends on how the auxiliary fence attachment is made, and whether it provides a separate means of clamping the far end. The typical TS t-square fence floats free at the back end. If there is any flex at all in the fence, that can be bad and/or dangerous for routing purposes. For routing purposes, it is also sometimes convenient to move only one end of the router fence to adjust depth of cut. That isn't possible using the TS fence as the base, unless the auxiliary fence provides that capability.
2) Any real utility to a miter track running parallel to router table fence? If so, what distance should this be placed at?
As you've noted, different folks have different methods of working. Some like to use a miter track for coping sleds and such, others prefer to simply run sleds against the fence. A miter track, or a miter/t-track combo can be used for horizontal feather boards, as well. So, again, the track is a personal decision, I think.
3) Many router fences have attached T-tracks to mount stuff off of, is this that useful?
I have t-slots in the MDF faces on my RT fence. I find them useful for feather boards, stop blocks, etc. Others may find them superfluous.
I note that Pat Warner suggests building a fixture when you feel the need of feather boards, etc. Not to put words in his mouth, but obviously there are various styles of working with a router table.
Pat is one of several good sources of information (and, router accessories - I have several of his bases). But, I think he would agree that there is room for differing methods, too, as long as those methods are safe.