Not really. Kuba is no better at defence than Cheech was as a forward. There is no way that they should be keeping him after the season is over. It's addition by subutraction.
Murray has said that Rundblad will play for Ottawa next year. He has not made that commitment to Cowan. Although, I am sure that it is probably in their plans.
It looks a little scary ... for the first couple of years anyway. 
Phillips-Cowan
Rundblad-Gonchar
Carkner-Karlsson
Lee
I agree with your 7. I would take the same. I'm not a Kuba fan at all. It's just gonna be tough to move that contract. I just don't like the whole buy-out process, and how it affects your cap for a couple years. Too many buy-outs can start to add up to a lot of cap space. If anything, we could just send him to the minors, make him go through waivers, and if not claimed, just bury him in the minors for one season. No need to buyout.
The defence will be young but with a lot of promise. The respective seasons both Cowen and Runblad have had this year has been remarkable. Every senator fan should be super excited. Cowen has matured, got stronger, and developed more offence to his already sound defensive game. Runblad has absolutely lit up the Swedish Elite League this year. He is currently 3rd in the entire league for points (49 points in 54 games), and as a defenceman to boot. Mind you, he is on the top team in the league with the highest scoring. But still very impressive. I know points aren't everything but just as a comparison, Erik Karlsson had 10 points in his final season in the SEL, Victor Hedman had 21 points and Adam Larsson who plays on same team as Runblad only has 9 points thus far this season.