Is there a way to edit the default settings of the WYSIWYG editor? So that the font, size and color are that of the rest of the site?

For instance, say my site had grey text, verdana, 8pt text all the way through on each page, what could I do so that is what the default settings are in the editor, rather than Times New Roman, etc.

You can choose 'Normal' under the editor Styles drop-down list. If you'd like to change the normal text, find and change .Normal in the default.css file to change it for the whole installation, or you can add/modify this class to the skin.css being used for your skin. This way it only affects pages rendered in your skin.