Jim,
There are lots of ways to handle this both when localizing the content and querying for the content.
If you enable the Combine with default culture
setting in CMS -> Settings -> Content
-> Multilingual
then when you use the IPageRetriever
it will return the default culture version if no localized version exists.
This would mean you could localize only the 2 field Page Type Pages, using the default (unlocalized Pages) for the rest of the site.