I like most of your plan. Trading Iafallo, Walker, and Durzi is a must. I agree with
@Herby, we need Byfield to step into a second line center role. Moving Arvidsson might not be worth it, but I'll play along here.
Kaliyev - Kopitar - Kempe
Fiala - Byfield - Vilardi
Moore - Danault - Kupari
JAD - Lizotte - Grundstrom
Anderson - Doughty
Gavrikov - Clarke
Bjornfot - Roy
Korpisalo
Copley
The big issue I see is that Kaliyev has yet to show that he can play top six minutes. If he can't, what is he? Not sure Kupari is good enough to play there. Turcotte hasn't shown that he stay healthy. I almost wish we'd trade for a 2C and keep Byfield at 1LW. Maybe Turcotte will surprise us all and take the 1LW spot? That'd be great. How about this for wishful thinking?
Turcotte - Kopitar - Kempe
Fiala - Byfield - Vilardi
Moore - Danault - Kaliyev
JAD - Kupari - Grundstrom
I think this defense could be pretty good though, and if Bjornfot's not the guy then we should trade him and some of these other pieces and find someone who is. How hard is it to find a left-handed third-pairing guy? Maybe Soucy? Not sure where Spence fits in, but he's got another year of waivers eligibility and Roy has another year on his contract, so I think it's either Clarke or Spence, and I'm sorry to say that I'd choose Clarke every time.
Anderson - Doughty
Gavrikov - Roy
Soucy - Clarke
¯\_(ツ)_/¯