It got a bad reputation back in the day because it wasn't an RPG and it got worse when Van Buren (Fallout 3) was announced and information about it came out. Tactics has locations that were going to be in Van Buren aka Fallout 3 but of course it would have been completely different than what was in Fallout Tactics.
So naturally people thought. "Well I guess that makes Fallout Tactics none canon then." The location was the final location in Fallout Tactics. So it was branded none canon and treated like crap since Fallout 3 would have negated Fallout Tactics' whole main story.
It also didn't help that Fallout: Brotherhood of Steel came out which is none canon, Fallout Tactics: Brotherhood of Steel's reputation was hurt even more.
And over the years people picked apart Tactics, pointing out all the "Canon breaking" parts of the game. Keep in mind many of the people doing that considered Van Buren Canon, even though it was cancelled, hell some people still do see it as canon. And alot of the "canon breaking" wasn't even true. Just made up horse crap. I had to debate some high level guys running one of the Fallout wikis to convince them that the Fallout Tactics section was heavily misinformed and biased against the game and it has been radically changed for the better.
Of course that is in large part thanks to Bethesda that has said that the "High Level Events" of Fallout Tactics are canon and even confirmed the Midwestern Brotherhood of Steel as canon by having mentioned them in Fallout 3 being in the Chicago area.
There is also another possible mention of them still being in Colorado in New Vegas. So for now I am taking all that as a sign that Fallout Tactics is pretty much as solid canon came until we get more information on the matter, hopefully in a future game. Tactics might still be treated like dirt in some corners of the Fallout Community, but it is getting more and more respect everywhere else.
As for your other question..