Do you have status at any airline? If not, the only ways to get extra legroom are to book business class (as opposed to coach) seats (but then that'll be prohibitive for your traveling companions who will pay cash), since it only takes 2x the miles typically, or to book coach on a flight that has Economy Plus on UA (most of them do) or Economy Comfort on DL (not that many of them do yet AFAIK). (AA has announced a Main Cabin Extra that's equivalent, but it won't likely be on the routes you'd most like in time for your trip.)

Power at the seat is tricky. All airlines tend to put power at the seat in business class, but in coach it various by airplane type and then is often only in certain rows. For example, in UA it may be mostly only in those Economy Plus rows on some planes. It's very hard to generalize. You have to look up the specific plane type (which you can do by flight number if you wish) at:

www.seatguru.com

and/or:

www.seatexpert.com

and it will tell you which seats are good and bad for various reasons (legroom, window alignment, etc) and will identify which seats have power at the seat and which don't. And will also explain what kind of video there is (that can vary by plane type too!).

Here's the thing: If you find a US airline which flies from the US to OSL itself, it may do that with smaller one-aisle planes that have very few amenities in coach. If you fly a US airline the long haul (DL from MSP or UA from ORD) to their European hub (presumably AMS for DL or FRA for UA), you'll be on a big two-aisle plane which is more likely to have amenities in coach, but of course you'll be connecting to a short-haul in Europe (and a short-haul in the US if using UA) on which there'll be few amenities in coach (but it'll only be a one-to-two-hour flight).

Keep in mind also that for east-bound, the longer the main flight, the easier it might be to sleep on it. Consider that if there are optoins to transfer in the midwest vs slightly cheap options to transfer on the east coast. You'll lose a couple hours of continuous sleep possibility by transferring to the TATL flight on the east coast compared to in the midwest.