Is it necessary for your group to talk about expectations and limits? If the group played D&D before, STA will be very different in style of gaming and definetly in the mechanics. It could be worth the two minutes to just make this clear.
When I did a one-shot test game of STA, I had one player complaining about the mechanics of armour/protection, claiming it was ‘highly illogical’ compared to the mechanics he knew from D&D. We could eventually talk through it, I hope, but it could have been avoided by properly setting expectations.
Regarding the limits: Star Trek can be (and should be, in my opinion) a very politically themed game. I love to see it as a game of moral choices and conflicting values (pun intended). But it can be difficult. So it might be worth it to discuss the ‘red lines’ of the players that must not be crossed by plots. Take this discussion about trigger warnings in/before adventures as an example.
I don’t know your group and maybe you were gaming for the last decades or so and this is not necessary for you and your group. But these are the things I will discuss out of character with my group in our session zero. 
Have fun, fellow GM.