It is adjustable so it can be 18", 21" or 24"
There is a set screw that holds the accessory to the mounting bracket, which is secured to the wall. (see install instructions) If you flip the holder over, the set screw will be on top, rather than on the bottom. If that doesn't bother you, no reason I can see why you couldn't install it that way.
Dark bronze with copper
These feel like made of Aluminum and had Oil Rubbed Bronze finish. Not too bad for the price. Great for builders.
Look under it, at the 6 o'clock position, right up at the wall.
You could contact the manufacturer but they use common drywall plugs and the screws are just bathroom type coated ones. Any hardware store has them.
Thank you for your question. Typically once an item goes out of stock, they are replenished within 2-3 weeks' time. If it is not back in stock by that time, you are welcome to reach out to our online team direct at 1-800-430-3376 as they can check their database for an ETA if it is available. However, each store has a special order bath catalog you can view there to see if there may be one offered via special order.
Thanks for asking. I would suggest and returning the item to your local Home Depot store. Products purchased on homedepot.com can be returned to the store. Simply bring the item along with your shipment confirmation email, order confirmation email or packing slip for ease of return. Most products have a 90-day-from-purchase return policy. Please refer to the following link for exceptions and more information. For any other questions, please call us at HomeDepot.com Customer Service 800-430-3376. http://www.homedepot.com/webapp/catalog/servlet/ContentView?pn=Return_Policy&storeId=10051&langId=-1&catalogId=10053&cm_sp=help-_-2podB2-_-returns3-_-returns_center