Her theory abut 'sweet' could be justified in in that 'meli' means "sweet" in Greek, and is an element found in many names and words (
Melissa, melifluous, etc)
But it is unlikely that Maliyah means all 3 things at once. If it's a Hawaiian-Arabic name (have no idea how this could happen without being made-up), it would mean 'bitter.' But if the 'mal' came from 'mel' it could mean 'sweet'.
"
Les yeux sont aveugles. Il faut chercher avec le coeur." --
Le Petit Prince,
Antoine de Saint-Exupery