Well actually not so many, but still a couple of them.

First, is there anywhere a table with all unit statistics? Like, where you can compare Hastati with chosen swordsmen and silver shields and numidian spearman and so on?

Infantery and cavallery are distiguished in "light" and "heavy". Is there any difference besides their statistics? For example, Hastati are light, princeps are heavy. Princeps have +1 attack and +1 defence if my memory serves me right. Is that all about it?

Spears. Spears are supposed to give you bonus vs cav. Is that really true for all spears? I am refering to those people that carry sticks rather than spears such as townwatch, lybian Spearmen, auxiliary infantery and the likes.