is there some way to integrate a dvd player through the mmi screen, without having navigation...?

I do not believe so.

It's my understanding that, if you don't get the Nav, you won't get the CD/CDR/DVD/DVDR player (you get the CD/CDR player without Nav).

It's my understanding that, if you don't get the Nav, you won't get the CD/CDR/DVD/DVDR player (you get the CD/CDR player without Nav).

True, but can an aftermarket dvd player run through the screen? hmm..

I don't even think it is the same screen. I drove a loaner the other day that was base (no nav) and the screen looked smaller with less resolution. The controls are also mounted in a different spot (on the dash) as opposed to the center console.