That's a brilliant question! I would assume that Tornio & Haparanda follow the same rules as the rest of Finland towards Sweden which according to raja.fi:

Those wishing to cross the internal border must use border crossing points where border control has been reinstated. Crossing the border in other places is not permitted without a border crossing permit. Self-quarantine is recommended for those arriving in Finland from countries subject to internal border control.

I'm not entirely sure if Haparanda & Tornio are among the places where crossing has been made possible again. I'll give the Turnio tourist service a call tomorrow to double check it! Worst case for me if the borders are closed at the end of the month:

• Organize something Swedish and wave to the non-swedes across the canal from either Haparanda or crab in another Swedish city if need be. (I rarely get to see all you Malmö & Danish butts)
• I rebook the last leg of the trip (Luleå -> Haparanda) to one of the national parks instead and go hiking for a weekend.

That would suck though... Really hope we can make Turnio work. I'll make the call tomorrow and get back on this.

I just called the "Finnish border service" they had this to say:

Crossing the border for (work related) conferences & meets (within the limitations of group sizes for those meetings) or family is ok-ish. The border security deals with requests on a case-by-case base as they arrive at the border up in Tornio.
the vague description I got off the lady taking my call suggested that it's pretty much just up to how an individual border security person feels about it that day.

The lady talking to me advised me to get some kind of letter/invitation/description of the meet from the organizing party, explaining why we'd need to cross the border. not necessarily as a requirement, but it would make crossing a tad easier.

She also mentioned that a new set of rules with either more or less restrictions might be released to the public this Friday and that we should probably contact them again (or watch online press releases) closer to the actual event date.

No big clear answer, but sounds like getting some paperwork sounds like a good idea @hoodownr.
Are you up to writing it or shall I write a letter that we distribute to people that have RSVPd for the event?
I have to write those invitation letters all the time when we fly volunteers over into Ghana... In that case they tend to be Visa request letters, but the same principle would apply for border crossing in this case ;).