Well yes - you must always have a power bit somewhere. (Well, almost always - many bits can vampire power backward through the bit, but that is NOT recommended.)
Theoretically your scheme is correct, but I don't have a synth (other than the PO14, and it just uses cv for its click track) that works with the cv bit. You would need to get a microphone bit and try it. But the microphone bit doesn't work very well as a microphone. If you already have a microphone that works with usb, try hooking it up through the usb bit.