1. Those are harmonic dampers. They reduce wire breakeage at the support clamps by absorbing wind-induced wire vibrations. They're similar to the dampened weights in the ends of modern motorcycle handlebars.
2. Those are typically grounded to the towers, and are considered as static drain, lightning, or 'neutral' conductors, although HV is usually transmitted as Delta, with line-to-line transformers, no real system neutral.
