1.Can the admin manage his profile?

Yes , he can manage his profile settings

2.How can he manage the email

Admin can manage the admin emails ie sender and receiving emails

3.Can the Admin manage the email templates,

There is no email template concept in xstreamerlite as it is only for guest users ( ie no users and models sign up)

However for admin, there is a forgot password template that admin can use for updating his password alone.

Admin–>Manage Email Templates