Handling read conflict in cassandra?
Mostly yes, but with small correction. You can get the stale data if they aren't replicated yet to another node (replication happens almost at the same time, but still could be delayed because of garbage collection, etc.).  You can get strong consistency by tuning consistency levels...

The comment is about point 3c - Cassandra's partitions are replicated to all nodes that were selected as replicas for particular partition - the driver or coordinator node can come to any of them, depending on multiple factors.  There is no such thing as an additional sharding key that will route to specific node - all replica nodes are equal.