I think it unlikely that the Pens include Cole or Sheary and even Jarry in any trade at this point as they are all probably considered crucial for the cup run this year. I'd love for the Pens to get Brassard but I think the trade would include the Pens 1st rounder as a starting point rather than current starting players. If OTT would retain some salary it could work.

How about 2018 1st, 2018 2nd + B prospect Conner Hall for Brassard with 1.25M retained?

It's worth noting that Washington probably matches any offer Pittsburgh makes on anyone, but especially on a spare 2nd line center at reduced salary, since they expect to meet the Penguins in the 2nd round for the third straight year, and might be getting tired of losing. Yes, Wasington has other needs, but they don't feel like matching Eller against Brassard, so if Pittsburgh offers a 1st and a 2nd for Brassard at half, Washington adds a 4th and a prospect (spread out over a couple years, preferably).

Penns likely don't want to lose Jarry, Sens will have 2 make it worthwhile. Extra pick may work.
Sens should add Jarry&Dansk from Vegas.