Yes, it is very interesting! Blew my mind once I started learning about it. Yes, I use the same product in the water and to spray the coop surfaces down. There are a couple different routes you can go with using EM in terms of which products to use.
The easiest, but more expensive route:
For...
I don't sanitize much of anything anymore these days. If I'm canning food, then I will sanitize jars with boiling water before packing, but as far as the chickens go, I generally don't bother.
I do scrub out their watering buckets (nipple buckets) most every time I fill them up.
I do put in...