Thanks for your reply.
One more question, When activating Avatar profiles is the a way of disabling the avatar upload from the registration form. There is no option to only make it available for registered users profile edit page ...
No, it's not available. However, if it's needed, you can easily editing the file components/com_osmembership/view/register/tmpl/default_form.php to remove the option to upload avatar
Once the modification is done, please move the modified file to PATH_TO_TEMPLATE/html/com_osmembership/register folder so that the change won't be lost when you update to future releases of the extension