No
Yes, you may have to use the screws to mount or stronger 3M.
Yes they light up as you approach the steps and not just when you step on the step. I do like the way they light the way on my stairs. Keeps me from fumbling for the bright light switch. You will most likely need more than one pack. I put two at the top so they come on no matter which side you start down the stairs, then I put 1 every 3 steps on opposite sides. It works as I don't want to add more. Replacing or rechargeable them quite often is annoying.
Don't know, .they have a slide for the batteries which are protected. I would ask the manufacturer.
No