1) Yes, of course. There's no way to set the whole of the east (OPFOR) side to anything using a simple variable like that.
The most popular solution for selecting everyone of a certain side is using a simple trigger:
Set up a trigger, name it something like all_east. Make the trigger area cover the whole of the island, or just all the opfor units you want to be affected. Set its activation to "OPFOR" and "Present", and make it repeatedly (just in case). Now you've got a list of all the OPFOR units on the map!
In your script, you can access this list simply by writing something like:
East_Units = list all_east;
And then you can assign aimingskill to your AI by using, for instance, forEach:
{_x setSkill ["AimingAccuracy", param1]} forEach East_Units;
I'm not entirely sure what you're doing in the description.ext with stuff like that, though...I'm not entirely sure first of all how you'd get the variables from there, and secondly it'd be far easier to just assign them to say a global variable in the init.sqf/run a script of some kind that decides these things.
2) No need to ask the same question in two places. Take a look at your original thread
Wolfrug out.