Help needed for notification

We are implementing a multisite solution using BuddyPress.

We need some help to set up the notification correctly:

1) if a user registers on the main blog, an welcome email will send to the user. If a user signs up from a subsite, our solution will automatically add the user to the main blog and network. However, the welcome email will not send in this case. What shall we do so that the welcome email will send to users who sign up from the subsite?

2) In the Welcome email, how can we include the user password to the registered user.

3) Right now, in the notification to the site admin, the user IP is displayed as How can we display the real IP of the user?

Thanks a lot.