The Sens plan to shed salary cap room is to waive Smith and Schubert and pay them $ 3.4 mil total to play in the AHL. Smith might retire (injury), and might be sent to Edmonton in the Heatley deal now that the Sens paid $4 mil (I doubt this).
So that's $3.4 mil that is easily disposed of. In Murray's interview, he said that Melnyk really wanted Kovalev (gotta have some more flash, they were interested in Havlat too, not at 6 years). So the owner said we'll worry about the cap later meaning he's willing to pay the big bucks to AHLers.
If the deal with Edmonton goes through, there's another $1.5 savings (factoring in Smid's new deal RFA).
So instead of being $2 mil over the cap, they will be about $2.9 under the cap once this is done.
If Heatley somehow stays with the Sens, they will be only $1.4 mil under the cap.
So no more moves (unless Heatley is traded soon), but they have a full lineup anyways.
*note: I'm not 100 % sure of the numbers, different sites have it differently. There could be a $1 million variation either way. But they're still under the cap either way with S & S in the AHL.