Winter in Norway - Lofoton Islands

When is this trip? There is a big difference between a december trip and a february trip to the area. I'd also suggest you spend the days in Oslo in the end, depending on your trip back home it can be a good idea to have a buffer.

Our options are flying Oslo to Leknes and taking two day trips ( one
each day) one west and the next east, then flying on to Tromso. Or
flying Oslo to Evenes, staying in Svolvaer (2.5 hr ride to Svolvaer),
next day one day trip (8 hrs) to Nusfijord and back to Svolvaer,

Again, when is this trip? For a winter trip to Lofoten, keep in mind that limited daylight and cloudy weather reduce the amount of scenery you can see. Also, the weather can get really bad.

Cruising is appealing just because we are seeing sites from the water
albeit some of the time we will be sleeping.

Are any of you prone to motion sickness? Hurtigruten is a great way to travel from Svolvær to Tromsø, but the sea can be very rough in the winter. Also, there is limited sunlight so make sure you have a realistic perception of how much you'll be able to see.

I am not a fan of small planes, and I understand Leknes is a regional
airport (smaller planes) and Evenes is larger, though we have that 2.5
hr bus ride to our lodging in Svolvaer.

Correct, Leknes is a small airport that is served by Widerøe and their DHC-8-100s (they look like this: https://upload.wikimedia.org/wikipedia/commons/c/c8/Berlevag-lufthavn-wideroe-dash8.jpg). Evenes on the other hand is served by A320s and 737s.

I guess we wonder where is the best, most scenic, authentic place to
stay in Lofoton Islands for two nights?

Define best please. For a winter trip I think Svolvær has an advantage as it is slightly bigger and offer more to do if your planned day trips aren't happening.

Any favorites in Tromso - Northern Lights cruise, safari, reindeer
sledding, etc. ?

If your goal is to see the northern lights, a cruise is to be honest a bad idea. And going to Tromsø is also not the best idea, taking the train to Abisko after Lofoten will increase you chances of seeing the lights.

Our trip is planned for mid February for about 10 days. Some of us are prone to seasickness, however my husband and I just sailed the Drake Passage to Antartica - I can't imagine it worse! Not to say we loved the sailing part, we did wear the seasickness patches for the first two days. However, a good point is made, perhaps the unpredictable weather makes a cruise less desirable. And thanks for the aircraft photos. So tell me about Abisko? We had thought of Kirkenes?

In February you will have daylight each day. Which is great if you want to see the scenery, less great if you want to see the Northern lights. The Drake passage can be really bad, just remember that Tromsø is over 10° higher latitude. But it's a pretty short trip so you might be able to handle it without problems. I'm not trying to talk you out of taking the ferry, just want you to be aware of what you might encounter.

Kirkenes is not that attractive in my opinion, what made you think of that city? While there certainly things you can see and do there, it's hard to get away from the fact that it is just a small mining town far away. Abisko is a great place to see the Northern lights. First and foremost, it is east of the large mountain peaks so in rain shadow. The mountain range means that the coastal areas in Norway are often very cloudy. It doesn't matter how much the lights are showing up if there is a thick layer of clouds blocking the view. Abisko also offers an unobstructed view to the north and a viewing station on the nearby mountain. Add very little light pollution and it is a very good place to watch the lights, in addition it is also easy to reach, around 1:30-1:50 from Narvik by train.

And something that is important to remember when travelling in northern Scandinavia in the winter, you do not have the final say on what to do and not to do, nature has. Never forget that.