Melodic and rhythmic tango is different Milonga is different Vals is different They are all different in music and in dancing, embrace looks the same but it's not. I strongly believe it's too early for learning milonga and vals. But as an introductionary level I feel it could be possible. Some light valses and milongas so the dancer can be acquainted with the music. I believe that they could be more motivated to carry on with AT, and say that "advanced" musicality. Beginners often want advanced stuff, so teachers must fullfil they wishes in a most delicate way suitable for them. IMHO the more they know the more they will appreciate really advanced dancers.