1. Three ways, Armatures, Lattice deformation, and Shape Keys. I'd go with Armatures, that exports the best.
2. You can't sorry.
3. You right click on the object. Go to object tab, (F7) far far left. Under object and links you will find OB:Something chance it to OB:Something else. There done naming.
Or click N, you should see it =D
4. I'll let a expert at Sketch up answer this one.