Yes. It will not only stop further lawsuits against you, but it will stop the pending lawsuit and the collection of any judgements that have been entered against you. In fact, if you have already been garnished, then that money that was taken in the 90 days before filing may be recovered as well. If you are facing these problems, then you should contact a bankruptcy attorney right away.
Yes, the automatic stay provisions of 11 USC 362 would prevent continued collection of same.
Depends on what kind of action but generally speaking g, yes.