We're only assuming that most of these are in the game.

Static formations for spearmen we've seen no indication of, and the arrow blocking with shields was only in the trailer, something which we don't know the full extent of its doctoring. Even if it is in the game we don't know if it's an actual formation, or just something troops automatically do while stationary.

Individual units are something that we've seen none of, unless elephants will be individuals, of which we don't know.

Gladiators in the screenshots are currently using weapons not unlike the gladius. IMO that's a bit redundant when there is a broader variety to choose from.

All we know of seiges are that there will be ladders and troops along the walls. Wether we can place them as we wish is unknown.