Last I knew, the principle around here was T5 supersedes all previous material for the purposes of canon, and if T5 doesn't address, it's the latest material.
I would presume Travellermap would need to be settled as to how canon it is.
Now that this poll has had over a week to circulate, and now that you have data...was your original thesis validated? Or did you find out something that you might not have suspected?
And how is this conclusion different from the one conducted in the other, but very similar poll, regarding canon in the OTU?
I've found that probably the best way to state what is "in" the setting is via a Guide which may gather odd bits together, and provides a list of extent published documents as resources that best represent it, instead of allowing all published material to be fair game. That way madness lies, to use Shakespeare incorrectly.
This could profitably be broken down further into milieu guides. The most important one would probably be
* Sharik's Guide to the Third Imperium, 1115.
Sharik could be the "main" Narrator, and Gannigar could be the "Contrarian" who occasionally pops in his head with a warning.
These polls have helped me form these opinions.