"
The Tears of Elune are one of the Pillars of Creation and embody the dream of what Azeroth could be." -
https://wow.gamepedia.com/Tears_of_Elune
"Strongly associated with healing, tranquility and harmony,
Elune is a goddess of peace, but she is not always a pacifist, as she does not advocate peace at all costs. One of her aspects is the Night Warrior, who takes the valiant among the dead and sets them riding across the sky as stars.[2][8][9] The Night Warrior is the incarnation of Elune's wrath." -
https://wow.gamepedia.com/Elune
What to gather from this:
1) Healing is restoring of life.
2) Tranquility is the state of peace; no fighting or war
3) Harmony is the the push-pull, ying-yang that life offers. Things must die in order to sustain life. Life and Death working together.
All sounds like LIFE to me!
The video you linked is EXACTLY what i referred to, thanks for linking it for everyone to see. What you failed to link is the events after that questline where we find out that Night Warriors can die. So based on this
FACT, if Tyrande dies, she goes to the Maw. If she dies in the shadowlands she still goes to the Maw (see newest cinematic of shadowland denizens being dropped into the maw by Sire Denathrius). If Sylvanas dies, she likely goes to the Maw to be reincarnated for as long as she wants because...:
"The laws that bind the Shadowlands are meaningless within the Jailer's realm. Reality is ever changing within the Maw, which is continually altering itself to the whims of its singular master[15] who resides in Torghast, Tower of the Damned." -
https://wow.gamepedia.com/Maw
/thread
It appears to me that YOU are the one that needs a source and the one who is making assumptions.