If I was the GM of team Finland
Kapanen - Hintz- Rantanen
Heiskanen - Jokiharju
Granlund - Barkov - Donskoi
Lindell - Ristolainen
Teräväinen - Aho -Laine
Nutivaara - Hakanpää
Haula - Lundell - Armia
Lehtonen - Kaski
Kakko, Kotkaniemi, Puljujärvi, Määttä and Välimäki are the extras.
My reasoning is that first 3 lines are all fairly balanced with clear strengths. First line is fast and dangerous and they played together for Jalonen as a line in 2016 when they won WJC gold, so previous chemistry is already established. 2nd line has great possession players, 3rd line has the Teräväinen - Aho pairing that will be also the main PK duo with Lindell and Ristolainen. 4th Line has Haula and Armia that will be 2nd PK duo with Heiskanen and Hakanpää. Barkov and Granlund can play PK also if need be. First PP will be Granlund, Hintz, Rantanen, Laine, Heiskanen. 2nd PP Teräväinen, Aho, Barkov, Lindell, Ristolainen.
Defensive depth is pretty bad and clearly the weakest of any top country, and the team needs to lean heavily on the top4. Luckily Heiskanen, Lindell and Ristolainen have been top25 in ice time for the last 3 years, so they can eat minutes.
I think special teams will be extra important and Finland has great special teams players. Aho, Teräväinen and Armia are all top 15 players in the NHL in SHP/60 for the past 3 years with Aho and Teräväinen being both top 5. Lindell is the SHTOI king in the entire NHL. PP should be dangerous as well with Rantanen, Barkov and Laine all being top 20 in PPGs for the last 3 years and Hintz was actually 3rd in PPP/60 in the entire NHL this season and 1st in primary PPP/60.
Rask and Saros are self-explanatory and Lankinen has proved that he can handle the pressure of a championship game.