No Mamoswine yet?
The others seem available, but I can't evolve into Mamoswine. How come?
Answers
You don't think they'll lump the remaining unreleased evolutions under the Sinnoh Stone as well? Excluding Gallade and Froslass, the ones added yesterday require knowing a specific attack in the main series. That attribute was not incorporated by any metric here in Go, and instead those evolutions were given the generic Sinnoh Stone + 100 candy requirement.
At this point I don't expect them to do anything different for the remaining unreleased ones and wonder why they didn't just release them alongside yesterday's batch.
My guess is that they are saving them for specific events. I wouldn't discard the possibility of a Magnemite CD by no means. It is just as likely as any. Niantic has proven time and again that they do now follow a defined set of rules when choosing their CD candidates, they have broken the "patterns" about every 2 to 3 CD cycles.