Was wondering if I spray with a Clorox solution, would this kill the stuff ?
If so, what % to use ?

Also, if dead, will it be more easily removable, with, e.g., just a hose ?

Maybe a little easier. I would soak it a few times in a solution of
water mixed with Moss-Out. One it is dead you could use a power washer
or a really strong stream of water through one of those hoze nozzles.

After you have cleaned the area, you could keep sprinkling some Moss-Out
granules when ever you start to see a moss starting up again.