Customization of CKEditor

Dear All
I am looking for some answer before choosing this editor for my project.

1 Can this product be customized to support DITA?
2 If we customize the product, what is the effect of this for any future upgrade of editor?
3 Can we add new buttons/ controls in the toolbar for any custom functionalies required to meet the business?
4 Does it support user supplied dictionary?
5 How can we add new words in the dictionary?
6 Does the dictionary supports multiple languages?
7 If I add a new tooltip for a button in the toolbar, what needs to be done for the localization?
8 What kind of paid support is available from the product?
9 What skillset is requied to customize the editor?

Advance thanks for your help.
Thanks
Saptarshi