Here the answers...
1)
As soon as you reach Break Point of opposing army or kill the General the game ends immedeately..
No close combat will be finished anymor.....it ends immedeately as opposing army decides to leave the battlefield....
2)
If unit is driven off the table you...
2.1. Roll immedeately 1D6 on the chart to see what happens to this unit (there are different results)
2.2. At the beginn of your own turn you can roll once more 1D6 if the previous result were that unit does not enter the table.
There are now different scenarios now.
If you started the turn it does not have much effect to you as you moved allready this unit....you only roll the dice in ther order mentioned above to see what happens to your unit for the next turn.
If you did not start the turn (meaning your opponent starts to move, shoot..etc.) and the unit got shot at and driven off the table then the result mentioned under point 2.1 is applicable for you this turn.
At the beginning of your turn you roll again 1D6 to see if the unit will enter the battlefield again.
At least we play it this way.....

3) It´s not clear what you mean here.....
I guess you are talking about a volunterely "fall back" or about "fall back" in general when you won close combat round. Right ?
You can move in any direction as long as you keep 1 cm distance to an enemy unit. The direction you move does not matter. You also can stay ground and say that you will not move but this you have to do before rolling the 3D6.
Regards
Claus