RE: a few new player questions
I am not familiar with the scenario you are playing, so I can't speak to the specifics. However, there is not currently any advantage to firing at a non-vehicular target from more than one direction. Only vehicles (and some fortifications) have a facing that affects fire attacks against it. There are some situations where a unit can only fire in limited arc (some fortifications, setup weapons), but generally units can fire in 360 degrees without any reduction of lethality.
My interpretation of the rules is that most weapons have four range values. They are CQB, short, medium and long. CQB is fire within a hex (ie assault combat) and uses the assault value for the weapon. Short range is one hex (double lethality). Medium range is from two to half the maximum range (normal lethality) and long range is from half to maximum range (half lethality). So for most bolt-action rifles in the game which have a maximum range of ten hexes, short range is one hex, medium range is two to five hexes and long range is six to ten hexes.
With that said, before you begin an advance against a prepared enemy position, it is highly desirable to obtain fire superiority. In game terms, this means you want to disrupt or pin those enemy units that can bring fire on your advancing troops. This halves their lethality and gives you a much better chance of closing with the enemy. Depending on the terrain and how close you can get to the bad buys, fire superiority may need to be conducted with heavy weapons and support (artillery and/or air strikes) if the range is long. If you can get close, you might be able to accomplish fire superiority with one infantry platoon while a second moves forward. This is even more likely if your basic infantry weapons outranges your opponents (you are armed with rifles while he is armed with SMGs). You can also accomplish this to some extent with the placement of smoke screens, but there are rarely enough smoke shells to this well or for very long.
So the answer to your third question really is "it all depends."
Hope this helps some. Feel free to email me if you don't understand the poorly written dissertation above. I have to get back to work right now.