Thomas is under contract through the end of 2019, so you don't have to think about addressing him until the end of 2018.
Snead is a FA after this year but I don't think he will be hard to keep. He's a quality player but probably seen by the league as a system guy. He's reliable and has nice production but it doesn't jump out at you if you're a GM trying to add a key WR. We'll have to gauge his value but I think it's easily doable.
Cooks is a FA after 2017, so we should address it this offseason. He's a talent and we'll have to pay him. But I don't think he commands AJG/DT/Julio money. We'll get it done.