FJ,
You ACED IT.
In Australia we has a "hit single" in about 84 which essayed some of the things you covered. We were at a stage where we could talk about Vietnam by then - ignore the evil politics of the war and focus on the human story. If you get a chance to look up I Was Only 19 (a walk in the light green) by Redgum you may like it. Is has a different impact to your song but different is always good. Your song has incredible impact and is sung/performed perfectly for the topic, time and purpose. Well done.
I Was only 19 - Redgum Oh, it was a hit again a couple of years ago - but as a cover by a hip hop band - odd but that's OK.
A mate & I wrote our own - but from the perspective of observing the evacuation...
It doesn't have the impact of yours and, as is usual for me, has too many words and not enough emotion - YOU get the balance right.
Solong Shuffle - Pygmy Beat