Wow!!---this sounds like a very challenging class----good luck!! Off the top of my head, the only thing I can think of is that, maybe, you could use your 'experts'--Native Speakers, as tutors/teachers in your classroom, and assign each 'expert' speaker 1-2 students to work with for the entire trimester...Here is why I am thinking that way: I feel that by doing this Native students will feel so appreciated, proud, and important that they are a 'teacher' in your classroom. In terms of what you could cover in the classroom with ALL students (to make it easier on yourself:), is current events---politics...Obama's Immigration law...Democrats and Republicans reactions....research the senators from your state, etc... I used to cover in my Native Speakers class a unit on Pablo Neruda, where we studied his poetry...and they had to write a poem using metaforas...I also covered a unit about Art----where we studied Picasso, Kahlo, Rivera, etc...we learned where these people came from...their families...their believes...etc. I know that I would be having a very difficult time trying to plan 3 different lessons for the same class...I had a hard time planning for one Native Class, which had different ability levels...but trying to do Spanish 3,4, and Natives----yikes!!!! La mejor de la suerte:)