Questions in two areas:

1. Splinage: What would be the optimum number of splines for joints? (Wrist, elbow, shoulder, etc) Do you need a spline for bicep flex?

2. In the instructions it says I need the "Mirror Bones" plugin, symmetrical model (CFA). In the unzipped folder, I have the Mirrorbone, MirrorConstraint, and the RMWeight .hxt files. Ho do I know its the Symmetrical (CFA) version?

I would say 3 rings for the joints is best ,The symetrical is your model needs to be symetrical not the plug in.It copy's from one side to the other with mirror bones so the splines need to be exacly the same position but mirrord .That where the cfa comes in ,its copy flip atatch .so you keep say the r hand side make sure all the cp's in the centre of your model ate at 0 z position then cfa it so that it is symetrical
shee thats a lot of tying lol