Trip to Lapland

I can try to help, what a wonderful trip for the two of you! I just returned from Finnish Lapland, so only know about Inari and being there in July. But I spent almost a year planning my trip and can share:
1) Finland is vast, and public transport, including flights, is very limited. You should consider driving conditions and your experience with that. For transport, for example, since Ivalo Airport serves Inari I (mistakenly) assumed daily flights. As your plans come together check flights before making hotel and other reservations! The bigger tourist destinations in the southern area of Lapland will have more services, leading to
2) There is not much information here! Trip Advisor has a Finland forum and most of the questions are like yours, for winter visits; you can search prior threads.
3) Look at Trip Advisor also for reviews of the options, including tours.
4) if you do choose Ivalo/Inari the Visit Inari company was reliable and very helpful for outings.
5) ditto for Paksvisit at Kirkenes- many posts are about the ice hotel, so starting there could work. This company was very helpful, also.
6) if you do drive, Lonely Planet ( at least in the US) was the only print resource I found.
Happy planning!

Finish "Lapland" falls more into the adventure travel category than Rick Steves travels. As a research starting point a Lonely Planet and/or Rough Guide book on Finland would help you identify areas and activities of interest to you. Our "Lapland" trip was one of our more memorable trips.

Our experience is a decade old and therefore a bit dated. We were on a cross country ski tour with guides that started by flying in to Ivalo (northern most Finland scheduled air service), then by local bus to Kiilopää Fell Centre south of Saariselkä, where we were met by a guide service. Saariselkä looked like one of the major winter resort areas near Ivalo.
https://www.kiilopaa.fi/en/home/2016/welcome-to-kiilopaa.html
http://www.inarisaariselka.fi/en/
Finnsair serves Ivalo from Helsinki.
Local bus/coach service from Ivalo: https://www.matkahuolto.fi/en/ and http://www.inarisaariselka.fi/en/airporttransportation/

I missed our ski association's trip to Rovaniemi but heard good things about the town. It's a major northern Finland tourist destintion in that the Arctic Circle is just north of the town. It's promoted as Santa's Village: https://www.visitrovaniemi.fi/

I'm sure that you realize that Christmas is a dark (few hour of daylight) time of the year:
https://www.timeanddate.com/sun/finland/rovaniemi
https://www.timeanddate.com/sun/finland/ivalo

The other (than Ivalo) northern Finland airport with scheduled Finnair service from Helsinki is Kittilä Airport. Our flight to Ivalo from Helsinki stopped at Kittilä before continuting to Ivalo. Kittilä serves the Levi ski resort, a large downhill (lift assisted) ski area: http://www.levi.fi/en/
These areas are very tourist oriented but may be crowded during the Christmas week: http://www.levi.fi/en/enjoy-levi/december-at-levi-christmas-and-new-year.html

Just returned from a 3 night, 4 day adventure with Santa's Lapland. Absolutely amazing time, so well organised, friendly helpful staff, lovely hotel (holiday club) and nice food. Would highly recommend.