1) Bridge:

Two armoured phalanx placed on top of each other and stretched across the end of the bridge so they just overlap the edges are unbeatable. Add a few missile units just behind and some cavalry for mopping up. For some reason sometimes the enemy routs TOWARD your forces and it's quite entertaining sitting back and watching them commit hari-kiri.

3) Corner of the map:

I've noticed if you set up too close to the red line, units sometime behave strangely (move toward the enemy for instance).

4) Attacking:

I wonder if a cavalry side attack is better so the enemy have somewhere to rout to (no fighting to the death).

I've more or less decided greek cities is best. I agree that romans are good, but they rout easily from a frontal attack on a good phalanx (triari are tough nuts though).