Yes! All the hard work has been done. The mycelium is fully colonised, and they are ready to grow some tasty mushrooms!
Generally between 1-2 weeks to get your first crop. They grow very quickly!
Generally one or two flushes from a boxed farm, two or three from a commercial farm. There is about a 1-2 week rest period between flushes where the mycelium will just sit and relax for a bit.
No! Oyster mushrooms actually like some indirect sunlight. So nearby a window is fine, as long as the sun doesn't beam onto them.
The bathroom or kitchen is a great spot for a few reasons. You are often in these areas, so it reminds you to spray them with water. Mushrooms like fresh air, and you often have a window slightly ajar. Mushrooms like indirect light, and these areas often get some sun. And finally, these areas have easy-to-clean surfaces, so you can wipe away any spores.
Growing some mushrooms to eat in your kitchen, bathroom, or laundry is fine. They will drop some spores if allowed to overgrow, but these can be wiped up with relative ease.