Don't think any of these trades really make much sense. Sbisa is probably they only one they'd really deal by opening night from this group (maybe Merrill), but the values on these deals are way out of whack.

Kings- This value is probably the closest, as the Kings could def. use Schmidt and a 2nd, 3rd and a guy who's had some AHL success and still relatively young is somewhat useful to Vegas (esp. 2018 picks which they are in short supply of). I think Vegas could probably do better, but it's close. I just think there is zero chance of Schmidt being traded before the season (esp. with the injury issue), and he isn't even likely to be dealt at the deadline. I think Vegas really believes he could be a long term option and if he has a strong year in a top 4 role he could be extended next offseason.

Caps- Speaking of long term assets for Vegas I don't think many are more valuable than Theodore. Not only is there basically no chance they'd trade him, but there is no reason why they'd trade him for this type of return. Barber is an okay prospect, but not really a centerpiece guy and Lewington really doesn't add any value. They aren't coming close to Theodore's value, and Vegas wouldn't even consider this deal even in Washington added a 1st round pick. On top of that you add in Orpik's negative contract value, which is going to cost a couple good picks or prospects to move on it's own.

Islanders- Vegas would do this deal in an instant, but no way NYI would consider it. Merrill is a solid 3rd pair or 7th defender option under control on the cheap for two years, but Pulock is a former 1st round pick who looks ready to make the jump to the NHL. The Islanders have control of him for 5 more years and his upside is far higher than Merrill's (even if this year he might not be as productive). On top of that Vegas gets another solid rental winger who has 20 goal and 40 point potential that they can flip at the deadline for a bigger return.

Ottawa- Sbisa is an okay 2nd pair option and a good 3rd pair option for a team like Ottawa and should bring back a 3rd or maybe slightly more, yet somehow Vegas retains some salary, gives up the better pick and gets an AHL body as the return. I could see him being moved to Ottawa for sure, but not nothing.

No chance that these are the guys that are moved except for Sbisa

Nate Schmidt was off limits to GMs trying to acquire him. I don't see how the summer would change that.
Shea Theodore was the crown jewel of their draft and can play one more season in the minors. No reason to trade him.
Ilsanders traded the 2017 1st to ensure that Pulock remained as part of their D core

I could see Sbisa moved to try to replace Methot but the Sens signed Oduya to do that. They're basically Phaneuf - Karlson, Boroweicki - Ceci, Oduya - Wideman so you're asking a budget team to trade for a $3,000,000 cap hit player to sit in their press box for a 2019 5th round pick and taking an AHLer back in Blunden. Again I just don't see the fit for the Sens.