Hi Gopa,
ad 1) Honestly ... I have no idea and also debugging the code did not enlight me :-(
ad 2) I would have thought this should work as you described. I cross check that and come back to you
ad 3) In my case it is the other way round. As mentioned no documentation, so I don't know the semantics. Nevertheless, it is part of the DB table that contains the basic ruleset information.
ad 4) This is not really related to the original query, so you should open a new question in this forum, to make it accessible for others. As a rough guidance: Which versioning is selected in your application? You find information on that in help.sap.com (Versioning - Business Rule Framework plus (BRFplus) - SAP Library)
BR
Christian