@Snow_Owl
Personally speaking, I only know enough vietnamese to pronounce it correctly out loud slowly and guess the meaning of a sentence by parsing out the words I do know. Wished I learned more when I was younger to be honest, LOL. But to answer your question: yes, the tone marks you see in the vietnamese language changes the pronunciation and meaning. An easy example that comes to mind is: ma (ghost) [where the intonation is pretty neutral] and má (mother) [where the intonation is high and sharp].
I honestly don't know enough to determine if there is a meaning to the name Lac Hy so maybe someone else who knows more can answer that.
Oh, sure. Its just a younger brother being possessive. Destroying any chocolates she tries to give another guy is totally within the realm of normal (and that is ignoring the supernatural means with which he did so).
I know the summary says this isn't incest, but even if the soul isn't originally her brothers but instead a magical being, the body is still... her half-brother, right? So genetically speaking, still incest