Gonna take a shot at this...
F1: Teräväinen - Aho - Rantanen
F2: Laine - Barkov - Kapanen
F3: Granlund - Hintz - Donskoi
F4: Lehkonen - Lundell - Armia
Replacements: Kotkaniemi, Tolvanen
D1: Miro - Jokiharju
D2: Lindell - Risto
D3: Välimäki - Hakanpää
Replacements: Mikkola - Kaski
G: Saros, Lankinen, Korpisalo
PP1: Laine(R) - Kapanen(R) - Hintz - Teräväinen
Jokiharju(R)
PP2: Laine(R) - Donskoi(R) - Rantanen - Granlund
Risto(R)
PP3: ???
PK1: Lehkonen - Barkov
Miro - Hakanpää
PK2: Aho - Armia
Lindell - Risto
PK3: ???
Comments:
The defense is clearly a weakness, and the team is still a couple years too young because of the lost generation. I put together this roster together with the intention of optimizing special teams. There are a number of guys left off who are legitimate choices, specifically on the wing, and I expect at least one of them will emerge as a more impactful player. I'd like to have Tolvanen as a starter, especially for the added powerplay threat, with Heinola brought on at #3RD and backing him on powerplays, but for now I can't justify moving anyone else off the wing.
F1: No reason to break up Aho and Teravainen, and Rantanen is their best match on the right wing, aside from being the obvious choice for 1RW. They can also use his size.
F2: Barkov might be the best center, but I think this more balanced approach works better. Also, Barkov is probably the best match for Laine, who clearly needs special handling. I'd also want Barkov and Laine playing slightly fewer 5-v-5 minutes that a top line, as they're important for special teams- Laine playing on two powerplay units, and Barkov on the 1st penalty kill. Kapanen has been impressive, can serve as the lines's forchecker/puck retriever aside from being a legit scoring threat on his own. (though I'm temped to match him with Hintz and Pulju just for the fun of a hi-speed line).
F3: Having Hintz as a 3C is great, and Granlund belongs on the wing unless there's no other option. I'd like to consider Granlund for #2W, as he played his best with Koivu as his center (that line had the best goal differential in the league, if I remember correctly), and Barkov is basically an upgraded version of Koivu. This would require some further shuffling of lines, though. Donskoi gets the nod over other potential wingers because he's a right-shot needed for supporting Laine's powerplay.
F4: This line will be playing very limited 5-on-5 minutes. I'd initially not wanted Lehkonen, as there are better-overall wingers than him, but none of them are as good as he is on the penalty kill (someone educate me if I'm wrong). Armia should be a lock at 4RW because of his penalty-killing. With Lundell, I'm making an optimistic projection. Maybe (probably) the coming season proves otherwise, and Kotkaniemi or Haula get the spot, but for now I like Lundell's progress and his versatility (can see him filling in gaps on powerplay or penalty kill). I'd love Komarov as a choice for 4C, but I think he's done with the national team. Maybe Luostarinen steps up for the job. Wouldn't be upset if Juhani Tyrväinen was chosen.
D1: Not comfortable with the top pairing, but you play the cards you're dealt. There's a lack of physical presence, so maybe Henri gets switched with Risto or Hakanpää.
D2: Some people don't even want Ristolainen on the team. Some people apparently aren't aware that Finland has a serious lack of right-shot defensemen. That he provides great physicality further justifies his inclusion. Expecting him to reveal a better version of himself in Philadelphia. Hopefully. Lindell is solid, and should be his most complimentary partner.
D3: Välimäki hasn't proven himself, but is the best option for now. Hakanpää isn't a star by any means, but... I'm ok with having him here.
Mikkola/Heinola is a tossup, and Heinola should definitely find a spot on future teams. I'll go with Mikkola for now as he's a defensive-oriented guy compared to Kaski (and Mikkola seems to be showing a steady improvement to his game). Kaski is currently the #4 Finnish LD... and probably better than that. Could see him getting several starts. Määttä isn't showy, but basically makes no mistakes, could see him making the team, but I'll leave him out. Juolevi or Lehtonen could make an emergence, and if Ohtamaa makes the team, that'd be ok with me. Some of the defensive lineups I've seen listed are too small/not hard enough. Being slightly more skillful doesn't matter if you're getting bullied all over the ice.
Goal: Rask will be recovering from surgery, and even if he's healthy, he'll probably be too out-of-practice. Saros isn't much of a downgrade, and I can see him and Lankinen alternating as 1A 1B. Kähkönen has looked better than Korpisalo lately, but for now I'll pick Korpisalo because of seniority, and the #3G will probably never play anyways.
PP: Not certain about these, besides having Laine on two shifts and supported by at least two other right shots who can pass to him on the forehand. Hintz and Rantanen playing alongside/behind the net. Kapanen/Donskoi in the middle. A 3rd unit would be necessary, but I'll leave that alone.
PK: It's be nice to have Barkov, Aho, and Heiskanen available for powerplay duty, but I'd want them well-rested for defending the disadvantage. Again unsure about the 3rd unit.