Scandinavia / Nordic Trip (Cities & Going up North)

While in Oslo visiting the excellent Viking Ship Museum there is also nearby the Norwegian Folk Museum, very similar to Skansen in Stockholm. Visit the one in Oslo to free up time in Stockholm for more sites there.
Oslo-do not miss Vigeland Sculpture Garden.
Stockholm: Drottingholm Palace where royal family lives. Take a boat out there, nice experience, and City Hall tour( very interesting) are highly recommended.

I made a similar trip pre-Covid and in summer, and didn't go to Sweden. RS hasn't much info for Finland, beyond Helsinki. You might look at Hurtigruten, I had never heard of this option- I sailed from Bergen to the Russian border final port to get to Inari- not sure you could do that in winter? They do stop in Tromso. They also arrange shore excursions. This was not a "cruise" in the traditional sense!
RS does have a ton of info for "Norway in a Nutshell" for the train between Oslo and Bergen, including Flam.
I really loved Helsinki! You might consider longer both there and in Copenhagen?

Check on when excursion boats sail. Some sail only in the Summer and not Winter.

Sounds like a great plan!

visit Copenhagen in Denmark, see the iconic colourful houses and
harbour, Tivoli Gardens, the mermaid etc.

Copenhagen is a great city, but the mermaid is a bit overrated in my opinion.

visit Stockholm in Sweden, go to one of the islands, eat at the
market, IKEA?, visit a museum - Skansen? etc.

The archipelago is certainly nice, but for a winter trip I'd suggest a short trip to one of the closer islands. The weather further out can be a bit miserable. If you are looking for museums in Stockholm, your first priority should be the Vasa museum in my opinion. A museum about a sunken warship may not sound that interesting, but I think it is.

see the Northern lights in a village up north: I have heard of Tromso,
Abisko, Rovaniemi, Alta & Ivalo. Not sure which to pick to fit my
itinerary, which would make the most sense geographically/logistically?

Abisko and Kiruna would make the most sense from a geographical/logistical point of view. Very easy to reach from Stockholm. Flights to Kiruna and overnight trains direct to both Kiruna and Abisko.

So I would like to ask if the itinerary is too rushed and what is the
minimum number of nights I should spend in each place?

It is not rushed, but not far away from it. If you can add a few days I don't think you would regret it.

To have a higher chance of seeing the Northern Lights, how many days
should I spend up in the north village?

The more the better. Even if some places have a higher chance of seeing the lights, there is never a guarantee. You have to remember that it is a natural phenomena.

Currently, I am thinking of this plan: Fly into Copenhagen (3-4
nights) Train to Stockholm (3-4 nights)

Good start, 4 nights is certainly better than 3 in both Copenhagen and Stockholm.

Fly up north to one of the villages: Tromso? Abisko? Alta? Ivalo?
Rovaniemi? (3-4 nights) I think Abisko would fit the itinerary the
best as flying from Stockholm to Kiruna is direct and EVE to Bergen is
also direct, and I've read that Abisko has a better chance of viewing
northern lights than Tromso and Rovaniemi because of the lack of
clouds.

Skip Finland, it is a bit of a detour from the rest of the trip. Abisko is as mentioned a great place to see the lights for a couple of reasons. It is a small village far away from any larger town so very little light pollution. Being on the lee side of the mountain range means it is in rain shadow and there is a very high chance of a clear sky. And there are direct overnight trains from Stockholm that stop at the Tourist station. The Aurora sky station on the nearby mountain top is also very popular. And if you are lucky you might see a great show: https://www.youtube.com/watch?v=as6foAVe4-I

But Abisko doesn't have reindeer or dog sledding.

Doesn't it? https://www.visitabisko.com/activities/dog-sledding/

I've read somewhere that in the dead of winter, Tromso has more to do
and is more beautiful (surrounded by fjords), But I would have to get
a tour for northern lights, dog sledding, reindeer, snowmobile etc.

Tromsö is a bigger town and a regional city in the north. So if you are looking for a city stay, Tromsö is the better option. But since the other stops are larger cities, maybe it can be nice with a stay in a calm natural environment? Tromsö is located at sea level with a moist maritime climate so the weather will be milder, wetter and cloudier. And you might need to travel far (a few hours) to see the northern lights or for any activities involving snow.

You might look at Hurtigruten,

Hurtigruten is a good way to travel along the coast. It is a mentioned not a cruise, but regular public transport along the coast. However, the North Atlantic winter storms can make the trip rather rough in the winter and best avoided if you are prone to motion sickness.

Thank you for your great comments! I will take those into consideration!

Abisko seems a little too small for my liking though. I’m scared theres not much to do in the day time (I know it’ll be short). Food may be limited. And wow dog sledding, snow mobiling and reindeer feeding is expensive! NL will be cheaper in Abisko.

Tromso looks like it has more options for accommodation, things to do. That cathedral looks beautiful. And theres a tour company - Polar Adventures that gives 20% discount on the tours if I book at least 3 activities.

So if I were to visit Abisko, it would be:

Fly to Copenhagen

3-4N Copenhagen

Train to Stockholm

3-4N Stockholm

Fly to Kiruna, train/bus to Abisko

4N Abisko

Train/bus to EVE airport, fly to Bergen

2N Bergen

Train to Oslo (I think Norway in a Nutshell would be too expensive and time consuming)

3N Oslo

Fly out of Oslo

But if I were to pick Tromso, I could work my way in a more logistical manner:

Fly into Copenhagen

3-4N Copenhagen

Train to Stockholm

3-4N Stockholm

Train to Oslo

3N Oslo

Train to Bergen

2N Bergen

Fly to Tromso

4N Tromso

Fly out of Tromso

I’ve found Turkish Air to have some good flight deals into CPH and out of either OSL or TOS.

Is the second one better?

Thanks,

James

We loved Scandinavia and found Norway to be the most scenic country. In fact, one of the most scenic countries in the World.
The best way to enjoy the fjords is to take a cruise up to the North Cape. Not sure that I would want to do that in the Winter.

Still, the best fjord was in Geiranger. Alesund is highly recommended, we did the excursion on the train that was great.
Tromso was good, but Geiranger, Alesund and Stavanger were better.

Abisko seems a little too small for my liking though. I’m scared
theres not much to do in the day time (I know it’ll be short). Food
may be limited.

I'm not sure what you mean with limited food, but you will not starve. The most common (and in my opinion best) place to stay is at the Tourist station, that has a restaurant. https://www.swedishtouristassociation.com/facilities/stf-abisko-mountain-station/ But yes, it is a small village. A great place for to stay for winter tourism and winter activites. But if you are looking for shopping, different restaurants and museums, it is too small. But you could also consider Kiruna. In the end I think you need to decide if seeing the northern lights is a top priority or if you want to travel north to see other things and the northern lights are just a bonus.

And wow dog sledding, snow mobiling and reindeer feeding is expensive!
NL will be cheaper in Abisko.

That was an example, there are number of companies that offer dog sled tours. Long or short, cheap or expensive. There is a huge selection to choose from. As well as other tours. Both in Norway and Sweden.

Polar Adventures that gives 20% discount on the tours if I book at
least 3 activities.

But also consider that Norway in general is a more expensive country than Sweden and that their prices in general are higher than Visit Abisko.

But if I were to pick Tromso, I could work my way in a more logistical
manner:

I can't see why Tromsö or Abisko would make such a big difference. There is nothing stopping you from staying in Abisko at the end of your trip, or in Tromsö in the middle. Which place to visit, and when to visit it are two separate issues not dependent on each other. For such a trip, I like to mix up cities and nature a bit and would prefer a few days in the north in middle of the trip instead four cities, and then a bit of nature. But that is just my personal preference and yours might be different. If you want to be back home when you plan to be, you really should not finish your trip up north. Travelling north of the Arctic circle means that you do not have the final say on when and where to travel, mother nature has. If the weather turns bad there is not much to do apart from stay indoors and wait. No mode of transport is immune to the weather in this part of the world.

I’ve found Turkish Air to have some good flight deals into CPH and out
of either OSL or TOS. Is the second one better?

It is in my opinion a bit early to book flights for a trip that is over a year away. And if you live in Singapore, my suggestion is to look at Singapore Airlines, then you will get a direct flight to Copenhagen (and a transfer in Copenhagen on the way back).