If you add some tylose powder or gumtex to the fondant it will harden and it wont need any other support. Or use gumpaste and let it dry. That is how I made this bottle. It is actually just a shell of the bottle.
Here is a tutorial. It is in another language but you can follow the pictures. Scroll about 1/2 way down the page and you will find it.
Yes you can if you put a layer of royal icing or even a crusting buttercream on them first. If they are that delicate, I would use royal to strengthen them up a bit.
Make sure the icing is dry before you put on your wafer paper or it will sink a bit as it dries.
Not sure where you are located but in California you can buy Pastry Pride at any Smart and Final store. It is a non dairy whipped topping which needs no stabilization and whips up stiff enough to make roses and stars. At Sams club or Costco you can buy Bettercreme or Rich's which is pretty much the same as Pastry Pride. Ask for it at the bakery. Take a look at my gallery, Pastry Pride is all I use, no buttercream or fondant.