Thanks for the feedback Admin... Being a software guy, I don't always consider everything...
The servos have approximately 200 oz-in of torque, so I don't suspect that will be a big issue.
The leg servos (and specifically the ankles) are going to have a lot more weight on them than the neck servos - I actually wasn't very concerned about the neck.
The tail is to help with balance while walking, yes. I hvaen't done any calculations because (a) I wouldn't have the slightest idea how, and (b) I haven't built the thing yet, nor do I have the kit, so I don't know what all this stuff weighs. I was planning on building and weighing the tail to counteract the weight of the cameras, whatever that ends up being.