Those droids in the whole betrayal scenario weren't on your ship. Quinn must have sent the specifications to Baras, who rigged them to fail, which is why Quinn says "I should have known...I was painstakingly precise." He knew Baras betrayed him because his calculations would have resulted in your death. The fight was easy for this reason.
That's an interesting theory, and would make a great basis for a fanfiction, but I don't really agree with this.
Baras wants you dead because you are becoming too powerful and are a threat to him (the apprentice that will kill their master in the end).
I don't really see him stage a doomed murder attempt just to unsettle you, he's too pragmatic to willingly waste an opportunity to kill you. The setup was probably well planned and meant to succeed, and seemed easy only for gameplay reasons (player being alone and the fight has to be doable by a solo player).
As for Quinn being insecure, keep in mind that not every female player made the same conversation choices. In the course of the romance you can really be a b.... to Quinn and he'd have every reason to mistrust you
That's just a shame that your choices don't have any real consequence on how the romance plays out.
I do believe that Quinn is completely loyal to you after the incident, based on what he says on Corellia + the very last conversation, but that's just me