As far as the lights, in my opinion you won't see them. I've only done 1 Alaska cruise, two Julys ago. I didn't see them. I lived in northern Germany right on the North Sea for 2 years, and I still never saw them, and every weekend I was coming home at prime viewing hours. Then in March of 2001, we were at the Orkney Islands, north of Scotland, we came in the wee hours of the am, after a night at the pub. The next morning, when checking out, the receptionist said "did you see the northern lights last night?". I would of given up every drop of scotch I had, just to have seen them. I was reading an article about Alaska, in a travel mag. This lady was in Alaska for 2 weeks, and never saw the lights. Part of the problem, is that they are more intense, visible after about 11 or 12 at night. Then the clouds have to be gone. When we were there in Alaska, we got quite a bit of rain, even our flightseeing tour was cancelled, due to lack of visibility. Even though, you will be very close to the earths magnetic pole, and they will be VERY intense and still swirling around, the midnight sunlight will more then likely diminish them, or prevent you from seeing them. It is worth a try though, if you really want to see them. Ask the captain, and other members who are on the bridge, if they see them at night. As far as whales, we only saw a couple of them, very far away. I subscribe to a "Aurora Borealis Forecast" website, it sends out email alerts, when and where the aurora will be visible. The alerts greatly diminish in the summer, the long hours of the sun prevent them from being seen. Well, I guess don't count on seeing them, and if you do, then I was proven wrong.
Hopefully, for your sake I will be. Good luck,