2. Yes. Plasma is about as advanced as it gets for everyone (except Zyyan). And it's not your Halo or Fallout plasma, this is the real-deal. Basically lightning in a straight beam; it makes the same noise and is visible for about as long.
3. More or less. It ranges from "Go back to the 1400s" to "Go back to WWI" in styles of looks. Warhammer 40K was, is, and always will be an inspiration.
4. Wheels or treads. If it looks like it could be used by Stalin's USSR, you're doing it right. If it looks like it could be used in Battlefield: 2142, you're doing it wrong.