My guess (since I'm not real involved with either team) is you're being a little optimistic to have Lehtonen involved. I think it'd be more fair without him, since I don't think ARI is looking for a goalie (especially at that cap hit with those stats).

Not a fair deal at all.

Lehtonen + Eakin = big performance & salary burden
Nichushkun = leap in the dark after 1 year spent in russian KHL

Based on what I've seen from Nill, I'm not sure he'd be willing to deal that many high-end assets in a trade like that. Swapping 1st rd'ers for Arz to move up + Nichushkin & maybe one other asset might make sense. Understood Ekman-Larsson would be a costly asset, but given all teams losing 1 asset to Vegas I'm not sure Nill would do a 5 for 2 deal as well. There's certainly merit to the fit for Dallas, I just believe the deal would have to be structured differently, and likely for both sides to agree.

If Nichushkin didn't want to play defense for Ruff, he certainly won't appeal to Dave Tippett. A more fair trade might be Honka/Eakin/two 1st Round picks for OEL/2nd Round pick

Probably the two first, Nisk, and Honka for OEL. ARZ doesn't need a player at #3 as bad as people think. They should probably be targeting Tippett/Tolvanen/Kostin so staying pat at #7 and not giving up anything for them makes the most sense.

Idk I think a trade with ARI would work great for both teams, as i don't expect OEL to want to go back to ARI when his contract expires