how long will it take for the Helium coins to appear in Cryptopia? I don't think they will appear instantly after the block 1644100. Maybe, Spreadcoins will also be locked for some time. In this case it will not be possible to sell them right after the snapshot.
Is block 1,644,100 even totally confirmed and 100% set in stone?
No. The blockheight for the snapshot is going to be
.