Great  - I think you have done a great job now and the article is looking better now it does put in the dates for each sister. I think that you have a good point about why it was rather stupid for the box to list "past members"  - also, to refer to "past memmbers" would confuse people and  
 may have led some to believe that there were still some current members, which   - now Patty Andrews has died  - is not the case.