1a. is done for single selected item or folder.
Selecting more then one item/folder is not possible.

1b. is not implemented

Thank you Yutaka.

Today, (2/28/2012) we are releasing EmEditor Professional v11.1.0 beta.
Updates from v11.0.5 include:
– (Snippets plug-in) The Cut (Ctrl+X), Copy (Ctrl+C), and Paste (Ctrl+V) commands were added to the Snippets plug-in.
These commands can be used to copy or move snippets items easily around the snippet tree.
The Paste command can be also used to insert a simple text snippet to the snippet tree.

Be aware: the snippet copy is an exactly 1:1 copy
including all parameters as f.ex. trigger and shortcut.