Habs aren't going to break off their only working line. Battling for the 9th place is too important.
IMO, they sign all three, keep em together and mix-up the rest of the wingers with either Suz or KK, but aside from Toffoli and Anderson, you have 4 wingers for 2 places left in the top 9:
Drouin, Armia, Lekhonen and Byron.
All four of them are, or soon to, cost too much to be on the 4th line. Removing Drouin and Byron clears up 9 mil that can serve for their extentions.
This said, because of this outlook, they'll stay pat and see how the other lines workout early in the season before they'd feel.comfortable sacrificing that line.