Sorry but it's a laughable notion that the Ducks would leave Silfverberg unprotected, not happening.
It's in Bieksa's best interest to waive his NMC for expansion. He's obviously not what Vegas will be looking for, so waiving is just a formality. He pushed for the NMC because he wants to try and win a Cup in Anaheim and doesn't want to move his family. If threatened with a buyout, he'll likely waive.
Can you provide examples of Fowler's name coming up in any trade rumors since the summer? I'm pretty sure the only reports that have come out during the season suggest that he's no longer available, likely due to the fact that he's been the Ducks best player this year on an overall basis.
It's becoming more apparent that the Ducks best course is to keep both Fowler and Lindholm to anchor the top two pairings at least until someone else proves they can carry those type of minutes. Manson has shown he is an ideal fit playing alongside either of those two, plus he's extremely affordable at least in the short term, and doesn't really have a peer in our system in terms of playing style. That makes him the next most logical dman to protect.
That leaves Vatanen as the odd man out, which is actually ideal because his role is the easiest to replace based on what the Ducks have internally (Theodore/Montour).
Moving Vatanen for a forward between now and expansion protection is the Ducks best course of action. This allows them to protect their entire core without giving Vegas a true impact player.
Protected
F - Getzlaf, Kesler, Perry, Silfverberg, Rakell, Cogliano, Trade acquisition*
D - Lindholm, Fowler, Manson
G- Gibson
Unprotected
F - Vermette, Wagner, Shaw, Boll, Cramarossa* (would be protected in the event that the Vatanen trade brought back exempt piece(s)
D - Stoner, Bieksa
G - Tokarski/Hackett (suspect you'll see one of these guys signed to a one year extension in order to fulfill goalie requirement)
It should be pretty clear to see that this is the way the Ducks should go, as it leaves them losing only a depth player vs a vital core player as you've listed in the article. I'd suspect if the circumstances I've outlined were to unfold, Vegas might be best inclined to enter negotiations with UFA Jon Bernier during their exclusive window.