Straight to the points:
1) When the Languages property is set the spellchecker is rendered on the toolbar as a splitbutton. When the user clicks on the spell splitbutton then it expands its dropdown and the user can choose the desired language.
The initial behavior of the splitbuttons of RadEditor is to expand their dropdowns when they are clicked for the first time but not to execute some command.
2) The current implementation of the ToolProviderID functionality does not apply the collections of the parent editor to the child editors. This means that the spell languages listed in the spellchecker dropdown of the parent editor will be not inherited by the child editors. The enhancement of this property is logged in our ToDo list but I cannot provide an estimate when it will be done.
In your scenario you should not set the ToolProviderID and manually define the languages for each editor.
3) You can have editors with different toolbar set of tools. Please see the following live demo for more information: Setting Toolbars
. You can learn how to remove tools here
4) For your convenience I have attached an example demonstrating how to create a symbol counter and restricted for multiple editors.
the Telerik team