Re: Can BuddyPress registration be separate from site registration?
Thanks for the heads-up, @gunju2221 
If by “BuddyPress profile”, you mean the fields and groups you have configured in the xprofile settings screen, then yes it’s certainly technically possible because site admins can create new user accounts without having to complete BuddyPress profiles. I’m not sure how to practically do this, however. Would need to try and find out.
Try to see if there’s a user registration widget (i.e. https://wordpress.org/extend/plugins/registration-form-widget/ — not tested) and see if it works and does what you want it to do.
(To clarify, there’s no difference between a “WordPress user” and a “BuddyPress”, both are the same.)
