The second point, yeah that's relevant.
On the first point, just give each person n-1 shards, each missing a different one. Then any 2 can decrypt. Or configure it for however many participants there are and they minimum number needed to encrypt.
On the first point, just give each person n-1 shards, each missing a different one. Then any 2 can decrypt. Or configure it for however many participants there are and they minimum number needed to encrypt.