1. Yes, you can place on sand or gravel. Not soil though - they will rot
2. If attached to a log or rock, you can just soak the entire thing. Alternatively, you can just mist them with a spritz bottle. I actually often do both. If they are glues to the log or rock, do not pull them off - you will damage them. If they are attached by their own roots, you can pull them off - the only reason they have roots is to attach themselves to logs, rocks etc. But once you pull them off, they are not easily re-attached - it will take/months for them to re-attache themselves.
3: only a couple of mine are in containers. Actually, if they are in a container, they will still need some air or they will rot. I have one sitting right on my mantle, no container at all. I have a couple of others sitting on a large sea shell.
Hope this helps. Also, go to YouTube - there are lots of really great videos on caring for them - you will learn a huge amount.
