My take on who might be coming and who's likely not:
Raanta - Contractless, plus has suffered from injuries. So unlikely.
Lehtonen - Contractless. Unlikely.
Niemi - Ditto.
Gibson - Ditto.
Ristolainen - A huge question mark. Contract ok, but... eh.
Lindell - Contract ok, might show up.
Honka - Ditto.
Pokka - Contractless, but still a maybe. Might have more to win than lose from a good WHC.
Puljujärvi - Contract ok, but said himself he's looking forward to quality practice. So unlikely.
Aho - Contract ok, might show up.
Teräväinen - Ditto.
Lehkonen - Contract ok. Has had a bumpy season though. But plausible.
Jokinen - Contractless.
Of the teams that might miss or make it in (and then exit early), Barkov has never shied from NT duty. So if Florida comes up short, he's a likely addition. Rantanen is another I chalk as possible. If Philly exits early, Filppula will be contractless. Lehterä has a standing contract, and might be motivated, but is there any use for him? If we get Barkov and Aho, then not much, I'd say. Marjamäki might disagree though.
To sum up, having Lindell and Honka for defense would be a good pair to build around. Forward situation would also be nothing short of stellar if we got all of Barkov, Rantanen, Aho, TT and Lehkonen. But it's good to keep expectations in check and assume we might miss at least one or two.
Then there's of course Tolvanen. Unless he pulls off another mean feat and somehow staples himself to the Preds lineup, he'll probably be available. At least he himself likely wouldn't say no.
The overseas goalie situation doesn't look good. Of course, that won't be a huge issue if Koskinen is willing. And even if he isn't, I'd be fully content putting my money on Rämö. Oh, right, there's Säteri. He's a maybe. But I'd still rank Koskinen and Rämö ahead of him.