Interesting idea Ray, but how would you explain Noah? To my mind it doesn't quite fit with the facts we have.
Selina would be fairly sure Noah's not coming back if he's been declared missing presumed dead while at sea. The other thought I had was maybe he met another woman overseas and wrote to Selina telling her wouldn't be coming back? Made a new life for himself abroad? Guess that would depend on the type of boat/ship he was on though, he may not have been travelling that far...
I like your thinking about George just saying 'George' as his fathers name at the wedding Jan, and the registrar assuming it was Gurman, that makes sense to me. And William George is a good find too, I think it's looking very likely the boys are all George French's children and the two girls were Noahs before he disappeared. And George jnr on freebmd is listed as George Richard Gurman - and on the census guess what George French's dad's name is? yep, Richard...
The other thing that's intriguing me about Noah is why I can't find a birth record for him. His christening is on IGI, but I've tried every variation of Gurman I can think of on freebmd to no avail. I've tried just entering Noah with no surname to see if I could get him that way, but still nothing. I even went through several years worth of all the South Stoneham birth records to see if anything leaped out as me as possibly being him, and nothing...