WPG TRADE: Although I really like the idea of Perreault coming to the Sens (as he is a poor man's Mark Stone), I don't see this trade happening for mltiple reasons.
I don't think WPG will be interested in Anderson (unless its at the trade deadline and they had injuries and need a backup where the other team is retaining 50% salary).
With Trouba gone, there is less cap pressure, and as much as Ehlers had a very disappointing season last year, he IS still young, time to rebound, AND on a team friendly contract. It would be unwise to offload him for the package they are receiving here as they could ship him elsewhere for a greater return (see Oilers).
That being said, with Trouba gone, they could be in the market for a 2nd pairing RD. Which may open the door for them being interested in Ceci. But his QO is going to be around 4.3 mil and likely still too much for the Jets (considering they still have to sign their RFA's).

TOR TRADE: Don't think Toronto will move Horton as his contract is insured and on LTIR (doesn't affect the cap). Marleau on the other hand, would be a prime candidate to move. But he would have to agree to it which won't happen unless its to go back to California.

EDM TRADE: The current value of Puljujarvi is not that high. The value EDM is receiving here is too great. It may be the Oilers asking price... but they are trading in a position of weakness (JP allegedly wanting out of EDM) therefor will not get this much. Perhaps a more plausible trade would be adding Manning (win win, oilers offload 2 mil in cap space, Sens get 2 mil closer to cap floor), and then replace the 2nd with a 4th or 5th and it may be more reasonable.

VEGAS TRADE: As per the Toronto explanation, Vegas has no incentive to get rid of Clarkson. His contract is also insured and on LTIR, therefore doesn't count against the cap. That being said, Vegas IS shopping Colin Miller, Reaves and Eakins to free up capspace. I'd look at those three as candidates to ship to the Sens.