Looking at the timestamps, should I assume that this second version is a correction of maria_gr's version?

If that's the case, normally one would leave a comment asking her to change her translation. That said, your changes are right.

My suggestions for both versions:
·I think "therefore" and "whom" are a bit too formal for this song (and for any colloquial conversation). I'm not sure about "lukewarm", and, as a non-native speaker, I can only say "it sounds ugly". ("warm" would do anyways).
·reversed should be "backwards" or "upside-down".

·The first verse is just a hyperbaton. I'd suggest to either:
··reorder it into proper English (the proper order in Spanish is Él era el dueño de tus labios, de tu tibio cuerpo, de tus noches, de tu fuego y de tu piel. Y de tu amor)
··tweak a bit your English translation (Your lips, your lukewarm body [...] your love were all his, or something more natural)

·Quién me lo iba a decir has that literal translation, but I think there's a better English replacement for that phrase ("Who would ever tell me" / "How could I ever tell"?)

·the verse that starts with "Sólo me basta la verdad" is wrong, it should be something like:

Only this truth is enough for me:
my warmth in your moisture,
falling/dripping all over your body.
You are my ticket to the Hereafter,
from where I don't want to come back.
If the universe dies
who cares?

·"Que la gente viene y va" means "People come and go, anyways"