Hi,
For renaming the font's, it's just like Vampothika said, about deleting the fonts,
Right now this option is missing form SKS7 but if you have the SKS Pro, first make sure
you have the settings "Show the code Editor tab" @ Tools > Preferences > Experience level tab.
Now, go to any section of the skin like "Edit Buttons controls > Push Buttons, got to the "Code Editor" tab,
you will see on top of this tab, a drop down button with the name "buttons" that is the name of this section,
click it and scroll and you'll all sections of your skin, fonts sections are called Font0, Font1, etc, select one
you want to kill and erase all the code. After that you will notice in your Fonts section that the font is no
longer showing.
Ps. after all I really want a "Delete Font" and "Delete Colour" buttons added too 
