Either one of the servo setups looks good for this machine. As far as the 350 rating on the keling motors, that is the peak rating! Do your design work based on the rated torque. The peak torque is basically a thou shalt not exceed rating or you let the magic smoke out.
As for the cad software, why not look at either progecad or draftsight (both are free) and they are look alikes for acad. For a cam, my personal preference is SheetCam (SheetCam homepage)
How are you planning on doing the Z axis? If you do the down feed mechanism, be aware there is quite a bit of backlash in the assembly. There are ways to minimize it, but I recently ran across a ballscrew setup done by Robin Hewlett (sp?) in England. Well thought out and uses a ball screw to operate the quill directly. The biggest advantage to his setup that I have seen over others is the ball screw is held quite close to the quill and minimizes the potential for flex in the mount to the quill.