BuddyPress.org

1) By default, an email isn’t sent to the user because the user password is sent via plain text (not a good thing security-wise).

You can re-enable this welcome email by adding the following code to /wp-content/plugins/bp-custom.php (create this file if you don’t have one – be sure to add PHP open and closing tags as well):

remove_filter( 'wpmu_welcome_user_notification', 'bp_core_disable_welcome_email' );

2) Please post the avatar bug on BuddyPress Trac:

https://trac.buddypress.org/newticket

Login with the same credentials you use on buddypress.org.

3) WP-reCAPTCHA is not compatible with BuddyPress.

BuddyPress uses a different registration mechanism.

You might want to try one of these solutions listed here:

http://www.bp-tricks.com/tips_and_tricks/stopping-the-sploggers/