I managed to get rebooked in the AY flights I wanted, following the two change of schedule emails I got last week. I also have layover of more than 24h in HEL (previous layover per original booking was less than 24h in HEL), so this is appreciated, even if these are not the ideal flights I originally booked.

The agent did insist that I would not be able to enter Finland even as a EU passport holder (I am doing SVO-HEL-FRA), but I saw in TIMATIC that EU passport holders can indeed enter Finland, if transiting through to their final residence country (which is Germany, in my case), so I think I should be good.