The more interesting question would be ‘what choices do you find more satisfying from a narrative standpoint?’ Is it better to play a Force user or a non-Force user in KotFE? Why? Is it a better decision to kill or to spare certain characters when given the option? Does it make more sense to you that your character would side with one faction or the other at a given point? There are not definitive answers to those questions but they can generate discussion.

True enough in that specific case but the Eternal Empire still invades and the Eternal Alliance is formed by the Alliance Commander with the help of Theron Shan and Lana Beniko to combat against it.

The basic premise of the game is canon. The broad strokes of the game’s story is canon. The PCs exist in the game’s world even if you’re not playing them but not much can be known about them definitively. What choices you make in the game cannot be known definitively but the fact your PC made a choice at a given moment is canon.

Or, to be clear, there is no canon in-game except what the devs have established themselves. The Hero of Tython defeats Vitiate on Dromund Kaas and the Warrior receives a message about it shortly after he defeats Darth Baras. There is no option to spare Darth Thanaton at the end of the Inquisitor storyline. There is no option for the SW to kill a certain companion for his betrayal. And Tyresius wasn’t killed by the bounty hunter on Tatooine (however much I wish that was an option). Those things decided by players are mostly a matter of personal taste.

This game has no established canon. That said, I think the SW would mostly make DS choices but there is a quest early on where an instructor praises him/her for a light side choice. Never waste a resource.

Depends on how you play your bounty hunter or smuggler.