Sorry if this sounds dumb...

[Irtaviš Ačankif]

Did EVERYBODY in the WHOLE WORLD pronounce "kameie" and all of the words with the <ei> infix incorrectly? 

Na'vi AFAIK doesn't have "ei" as a diphthong, so I think that instead of "ka.mey.ye" we should pronounce it as four syllables as "ka.me.i.e" according to the meoauniaea rule?

Did Frommer have an explanation why "kameie" is three syllables, since he pronounces it as three?

[Kayrìlien]

It's always "officially" been a four-syllable word. It's always been pronounced as a three syllable word, unless people are trying to speak exceptionally clearly. I would imagine it's one of those words that is so commonly used that it would eventually become diminished/contracted over time, just as "God be with ye" has become "Good-bye" in English.

The meoauniaea rule exists as a rule of thumb, and should still be followed in the vast majority of cases. The whole diminution/reduction thing shouldn't be applied across the board. (i.e., don't pronounce it as [me.wau.'nja.ja])

Kayrìlien

['Oma Tirea]

A tricky word where the e and i in <ei> sound like ey: p<ei>ey (and similar).

I have made myself sure that kameie sounds like 4 syllables and not 3.

[Ikran Ahiyìk]

It sounds weak, sounds kameye but usually it's not in fact.. still an i there.. or the sources you are listening to isn't mine. For mine there are still 4.

When I was first knowing this language, I had tried to pronounce it as clear as the other 3 syllables, but it sound VERY harsh and weird.

[Tirea Aean]

yeah seriously the difference is so minute, no one cares unless you want to talk extremely slowly and clearly.

[Ikran Ahiyìk]

Something like this
A message from Paul Frommer

It's kameye-ish I heard but the truth that it's with an i can be clearly got.