As for Nahakhontl, I was using the original iambic stress system (every second syllable in the sentence is stressed). I have since decided that this is only a higher register, while your average person is going to simply have stress on the second syllable of a word. Sometimes it amounts to the same thing, sometimes it doesn't.
My Maja there is horrible, to be honest. I kept mixing up the length allophony. All orthographically monophthongal vowels except /i/ are supposed to lengthen before /r/, regardless of whether or not that vowel is stressed. But length seems to really like stress, because I kept either stressing r-lengthened vowels, or lengthening stressed vowels not before /r/.