I can't find a likely candidate for Alfred Green on the 1881 census, neither can I find a death that I'd be sure off.
He may have been dead by 1881 or he may not have been. You've got to remember that a lot of people couldn't read or write and censuses were taken by an official. Mistakes happened.
I can't see any more likely children for Alfred & Naomi.
George Canning Hodges was the second man she married, Naomi is listed as Green on the registration.
On the 1891 census it appears Naomi is listed as the wife of a George Murry. There's a lot of errors for this listing (her mother is listed wrongly as Green). I don't know if these are just transcription errors or wrong on the actual census. The details for George Murry are consistent for those of George Canning Hodges(b185o Bristol) and as he doesn't seem to appear on the 1891 census, I suspect 'George Murry' might be George Canning Hodges.
That they don't marry until later is not uncommon.
If Alfred was away in the army, would this maybe explain his absence? I dont have subscriptions so ive googled Alfred Green Warickshire born est date 1854 and it brought up links to army records, I know its not certain but im not able to view them to check.