Japanese - Ask questions thread

Basically if you have a question about the language, ask it and fellow 4channers might see it and answer it for you.

To start it off. When an animate object (iru) dies, is it considered inanimate(aru)?

Ii(good) has another reading, yoi, right?
If so, which one is more commonly used?
I often hear "Yoi shuumatsu wo" (have a nice weekend)
or "Ii ja nai ka?"
Or does it depend on the situation?