Changes like this in a keeper league I always feel should only be implemented for the upcoming season if they are in 100% vote with everyone in agreement.
If it is a majority vote I feel like these changes should be made one year out. Thus giving managers a full season, a trade deadline and one full offseason to accommodate the changes for their team.
However it looks like the decision has already been made..and you will just have to deal with this punch. Obviously lots of the other owners have the top FO guys and wanted to five their teams an advantage.
Koivu I would suggest is a decent option to bounce back...but his age and salary are major hindrances.
Zajac takes a lot of faceoffs, but this duty will likely diminish and Hughes and Hischier get more accustomed to the NHL.
I think you might be best to take the cheapest option salary wise and use the remaining salary to aim for other stats and then hopefully be leading in other categories enough to make a swap somewhere.
But like you mentioned, those with FOW centres just got a whole lot more expensive.