Regarding the clutch switches:
As you know, there are two of them. The first one engage when you barely touch the lever, and it will disengage the cruise control. In most cases the switch will make contact at such an early stage that the clutch still remains engaged.
The next switch will engage when the clutch lever is all the way in, and this allows for starting the engine when in gear. The switch is adjusted in such a manner that it ensures a total clutch release.
Hence, relying of any of these two switches would be a bad idea. Th CC release will engage way too late for a smooth takeoff, and the in-gear-start bypass switch will engage way too early...