I should add to the above that Lucy was living in London whereas Thomas was down the road in Guildford so I do think you are probably right that the baby is Thomas’s.
Another thought... Emma married in 1877 so I guess it’s possible that one of the identified men could be her husband or fiancé. They married in Sussex and lived there though, so as with Lucy distance may be a factor.
Finally, do you think it’s possible that the daughter top left could be ten years older than the daughter top right? If so Emma and Sarah could finish the puzzle with all the others as per your numbered photo.
