Actually, it is a simple coding change to switch from a radio button. But then you must store the answer in the database and interpret the answer when displaying.
Since there is only one database field for each set of radio buttons, a programmer might (for example) set the data for Suffix to "certain|uncertain" if you had chosen both. Then when the data is redisplayed the next time you edit the profile, the programmer would need to change the display code to check both boxes. This is a fairly trivial task. Of course, it would make the result illogical.
Even more illogical would be a birthdate that is marked "about/uncertain|exact/certain|before this date|after this date|blank for extra privacy". No, don't tell me this won't happen. When you give people the opportunity to do silly things, they will. It is a corollary to Murphy's Law.
So, let's address the problem by recommending an extra radio button that is labeled something like "none" for each of these fields. When the edit page is re-populated, "none" never shows as selected.