Nina,
Did you import the new EDD into the template that is used for the XML import?
In a list of context rules, there is the "else" rule that should satisfy your second question. Also, formatting is applied in a cascading manner. If you want to set a default for "body" elements, put the formatting rule on that element. Then, if no subelement has a rule which overrides it, the default is applied.
Russ