I think that character generation is a very central (and archetypal) part of the Traveller experience and therefore the starter box should have some character generation rules, probably only of a few careers (the core six from Classic Traveller, maybe?).
You should probably also give the prospective players a taste of all the Traveller staples - some exploration, skill/social challenges, personnel combat and basic ship operations/combat. No need for generation tables except for the character generation ones, but I think that the starter adventure should provide a robust taste of what's Traveller like.