It really boils down to what kind of Traveller game you want to play...Beancounters of the Beyond, where you worry about starship mortgages and cargo manifests...or Swashbucklers in Space, where you and your friends raise merry hell and upset all the damn applecarts you find as far as loathsome canon goes...or something in between.
If these cats have been hip to the heroic and cinematic games such as DnD, then you may want to chuck most, if not all, canon, and play in whatever setting you choose.
What it basically boils down to are three simple things, really...
3. It's a science fiction game, which tends to run heavy on the "science" as well as the "fiction".
2. The TU you decide to play in is...well...the TU you decide to play in. It doesn't have to look like ANYTHING anyone else is doing.
1. The goal of this, as well as any, game is simple. Have FUN! You want lightsabre-wielding Solomani Sushi Chefs? Well, BLAMMO...there they are. As long as it makes sense to YOU, that's all that matters, and straight to hell with whatever anyone else tries to tell you about the "official" game.
Enjoy...and good luck! May your first adventure in the far future be the first of many!