transactional replication locks

I am trying to understand some of the doubts while working on transactional replication in SQL server 2008 R2. Even though I was reading it in TechNet, may be some one can explain the way easy to understand about how locks are placed in the publisher while taking snapshot and at the subscriber while applying the snapshot.  Below are my questions.

1.  When reinitializing the subscription with new snapshot, shared locks are placed on the article at the publisher, so users can read the data but they cannot update while snapshot is taking right?
2.  Do the distributor agent copies the data using the snapshot to the subscriber by overwrite the existing data or deletes all the data and writes with new one?
3. While snapshot is being applied what lock is placed on the subscriber?
4. Let’s say if reporting team is running some reports at the subscriber, do the distributor agent will wait until the report to finish then applies the snapshot?

Thank you so much in advance.

VR