No, I personally don't like arbitrary default programs (ie Google); I believe the choice of a search engine should be left strictly up to the user. Suggestions are already made in Firefox, surely users can exercise their own choices in choosing one.
No, I personally dislike default add-ons, (i.e. Google) so I think the choice should be made by each individual as to which search engine they want to use. So no default with StartPage. There are several choices from which to choose, provided by Firefox.