Is Carbon Steel strong for swords?
Yes. Most high quality knives are made of carbon steel versus say stainless steel. High strength carbon steel holds an edge well and is strong.
Depends on the sword design. Some swords are high carbon, some a low carbon, some are made from a billet of alternating high and low carbon ('Damascus' steels). It all depends on what characteristics you want for your sword. Softer steels won't hold an edge as well but they offer great flexibility so your sword won't shatter when they make impact with armor or shields. Harder steels hold better edges but they're prone to binding in wooden shields and then being broken as soon as a bending force is applied along the weak axis of the blade. Japanese Katanas have both hard and soft steels to allow the blade to bend yet still hold strong edges. If you're making the sword from raw materials on your own, look up some different recipes for crucible steel. It's probably the most fun and involved process.
