Presumably they believe that Xayah is too powerful to give away (ban trends throughout the series seem to indicate both teams like the champion) and that giving the otherwise mega lane-dominant duo of TL a more passive set of champions would be good for them.

Tristana is actually great in this draft IMO, but hinges on whether or not you believe Karma is worth the priority you're giving her. To me, I don't have issues with what Clutch drafted, I think they navigated the situation very well. It's more whether or not you should even be in this situation or not that's the question.

I feel like if you're going to test your mettle against Sona, you're better off saccing game one rather than game five to test your hypothesis, but if you follow their thinking it's not bad drafting IMO.

It's easy to say now that it's "bad" if you're being results-oriented, but again if you follow the thinking it at least makes sense, even if ultimately it was not the correct plan for the last game.