So, I took a first look at the Rig. And I decided to split up the corrections for the Leg and the Arm into two comments, since I started with the Leg and I found quite a few issues. I'll take a look at the arm later today.
The problems is see are the following:
1) The knee joint is connected to the IK/FK switch the wrong way around, so the Knee is in IK mode when the rest of the Leg is in FK mode and vise versa. This is the biggest problem, but it can also be easily fixed by just reversing the two connections on the knee switch constraint.
2) The visibiltiy of your controllers is also connected the wrong way around. So when your leg is in IK Mode the FK controls are visible and vise versa. Once again, just changing those connections should work out.
3) The pole Vector is aiming at the wrong target. The left leg Knee is aiming at the polevector control of the right leg. Just redoing the pole vector constraint for the left leg with the left leg target should fix this issue.
4) your twist setup doesn't really make sense. Both thigh twist joints are in the same position while the ankle joints are offset from each other, also there aren't any twist or roll calculations going on on any of them and there is no way to access them using a controller. So currently they are just additional joints that need to be painted but they don't do anything.
5) You dont have a foot control. I'm not sure if you just wanted to set up a direct FK control for the foot and haven't gotten around to it. But I would encourage you to extend your IK/FK Setup to the foot as well, legs are in IK mode 90% of the time so having a good IK foot setup will literally save you hours of work in animation. If you want some good foot tutorials, let me know and I will link some.
If you fix those things, your leg should behave more or less how you want it to. But I also have to mention, that the joints aren't oriented correctly. In the default stance all joints have more than one non-zero translation channel (they should have 1) and some of them have non zero-rotations, this will make it impossible to implement squash and stretch and it can more easily lead to gimbal lock problems during animation. So if you want your rig to be optimal, you should probably diconnect the setups, from the controllers and each other, orient the joints correctly and redo the connections.
I know this sounds harsh. It's probably the first rig you are building. But believe me, a good rig will save you a lot of time in animation and the rig you have right now in the leg will cause you problems and headaches down the road.
I'll write you about the arm later.