@ Pontius Pilate
For your C answer, I feel soo sad to learn if that the best Byzantium units in Crussaders is just a Fantasy units... but at least I now read so interesting articles about Greek cannon, made by Archimides

http://www.mlahanas.de/Greeks/war/CatapultTypes.htm

Could the EB II had the Archimidean Steam cannon units for Syrakousai or Koinon? it can made into reform units such as "Archimidean Reform" and the Prerequisite is built the highest Academic structure in Syrakousai...