On your arms you need to add a IK RP (rotate plane) which will let you control the way the elbow bends, the IK RP will go from the shoulder joint to the wrist.

It looks like it is missing a lot of things. I am loving the look of the character, nice work.

I have attached a file I just made of a simply arm setup.

I will look over your file when I have more time I am a newbie myself to this but I will look over it and I am sure other people will too.