Check QZ gallery there are some pictures of Queen members with their children, as I remember. Roger in cinema with his kids from the 90s, you can see John's kids on Champions Of The World video (footages from 70s and from FM Tribute rehearsal), etc. etc. etc.
You could also check the press agencies sites like this Gettyimages,Topfoto or Corbis:)Just fill the name of each member in the gaps of the search engines and you'll seec also their kids:)!