1) Human beings vary in how close they are to developing a mental body. Some are on the brink of doing so, or have actually achieved it -- we call these latter individuals saints, sages, and adepts. The material body remains largely unaffected until the end of the incarnation when that happens, but that's their last material incarnation.

2) Yes. Wood is very good at conducting and storing subtle energies, so any wooden object that is the focus of emotion and attention develops an elemental soul, which lasts as long as the object does. A violin that's had several owners and been played many times can be quite lively, and have decided opinions.

3) A good point!