Each satellite is independent of each other, so all filewalkers working for them are running independently too.
it’s possible, yes. The sizes of the pieces are vary, your node stores only 1 piece from 80 for the segment of data (64MiB or less). If the segment is less than its Metadata, it’s stored as an inline segment on the satellite itself, see Understanding Hierarchical Data Structure and Advanced Terminology - Storj Docs
it has data signed by your node, it’s cryptographically proved.
However we could have a bug in the generation of the bloom filter - it could cover not the desired amount of garbage, like not 90% but less or skip some too small pieces or nodes, etc.
I can see only these: Issues · storj/storj · GitHub