The new operatives introduced this event are:
Acacia - Chrono Echo <-- click to go to her article Click here for my opinions on Chrono Echo
Marian - Aquila <-- click to go to her article Click here for my opinions on Aquila
Aquila is freely claimable between the 12th of Feb and the 12th of March.

Snowbreak went into maintenance mode on the 3rd of March.
I have no idea when it'll finish, but you'll get a free 6* operative and weapon selector in the mail afterwards.

I could give you an explanation of why, but the TL:DR is that Snowbreak were planning a collab with China Post (who do collabs with gacha games pretty often) and some Chinese idiots didn't like that. China's bad laws being enforced badly can mean problems, especially when enough trolls and bot accounts complain.
More free stuff for us though, which is nice. Apparently the selector will go up to v2.8 Fragments of Truth (that was the patch of Vidya - Celestial Swan).