That is way too much to pay for Contreras. He's going to be 33 next season and is still owed 54 million. On top of that, he's not much of a defensive upgrade over Ruiz. Honestly, Ruiz for Contreras straight up would probably be an overpay, but closer to the mark. But you would want to DH Contreras an awful lot.
Turner played 6 games at third base. At 40 years old, I think his days at third are over. Frankly, I think his days as anything more than a bench bat/light side platoon hitter are over. I don't see him being more valuable than Tena or Lipscomb at third, and I just assume we think of Turner as a placeholder until House is ready.
Trevor Williams just doesn't seem capable of being a starting pitcher. Last season, he was serviceable through the first 10-12 starts, and then fell off a cliff. This season, he made it 11 starts before getting hurt. Its cheap enough that you can throw him in the bullpen, but I think he is determined to be a starter.
You're selling low on Abrams. The most the Mariners are giving up is Miller. And Miller ... Miller is complicated. His Home/Away splits are jarring. Away from Seattle, he as a 4+ ERA. Normally, I'd chalk that up small sample size, except Teoscar Hernandez did an interview where he complained about the batting eye. Jon Morosi did some digging and confirmed it with several players. Moreover, Miller's advanced stats back it up. His K/9 at home this season was 10.37. It dropped to 6.43 K/9 on the road. His home run rate tripled. But his walk rate was pretty similar (2.15 BB.9 at home vs 2.36 on the road). Last year his numbers were pretty equal, so maybe this is a fluke, but Miller seems a lot closer to Jake Irvin than a top of the rotation guy.
The money and prospects you're sinking into Contreras, Turner, and Williams could be invested in a better starting pitcher.