2. Right now the cheapest source of hydrogen is to strip it from natural gas. In practice it's still a fossil fuel.
3. Using the heat from high-temp nuclear would let you synthesis fuels with higher energy densities, that are much easier to transport and store, and can be run in conventional engines with little modification. Methanol, Dimethel ether, and ammonia are potential candidates. Heck the navy is even has some success with JP8.
4. Moving from fossil fuels to wind and solar is a step backwards. Nuclear is the way forward for reliable energy and property. If the U.S doesn't do it, India and China certainly will.