As has been said, Flashlights are currently impossible. If you examine the HK's model you'll see points on the Memory LOD for them, but BIS must have changed their minds about implementing it into the final game.
As for random faces, I beleive that is all about the definition of the units in the Config.cpp. and how the sections are defined in the model its self.
Here is an example of the Class CfgModels section of a unit to get "random" faces.
class CfgModels
{
class Default {};
class Head: Default {};
class Man: default {};
///MEN
class CLASSNAMEofMan: Man
{
sections[] =
{
SECTIONS OF MODEL HERE
};
sectionsInherit=Head;
};
class ModelNameHere: CLASSNAMEofMan {};
};
I hope that helps you out.
And as regards the shadows etc, to solve that, you have to have LESS than 300 faces in a LOD. (Not sure which LOD, but I think it says on the Official Forums.)