It's tough to say what you do with Zadorov IMO. I definitely think we need to wait another year before negotiating long term with him. He was still too inconsistent from night to night for my liking this season, and while he looked to be getting better at this as the season wore on, I'd still want to see one more year before committing to a long term deal yet.
The thing about Zads is he's likely never going to be a huge point producer, not with his limited PP minutes. So even if he does put together an 82 game season next year playing at the high level he's capable of, he likely still only tops out at maybe 35 points. So he wont ever get the biggest deal on his next contract regardless.
I think waiting until summer of 2019 to negotiate with him would be the better course of action. Unless you can get him to sign something that starts with a 4 for 7-8 years this summer, otherwise just see what he brings next year. At most I think he's only going to get 5.5-5.75 on his new deal.