Oh God. There's an Alfred in Downton Abbey! An Alfred who is, moreover, a footman on his way up the ladder!
So, so, so, in my head, this is the perfect moment for a backstory. We know Alfred Pennyworth gets a checkered and/ or colourful backstory in the few times we hear about it (Nolanverse Alfred has military and/ or army medic experience while there have been a few mentions in less positive storylines about Alfred being an actor before he becomes a butler) so this is the perfect 'in' for him!
In this case, this is his father or grandfather- who's probably about 19 or 20 in 1921 according to the show - who gets his feet firmly onto the butler-ing ladder. Then the world turns, the world that requires butlers vanishes, and Alfred does end up doing a whole bunch of very exciting things. And I'd like him to be an actor, because I think it would work towards the thought of creating the perfect butler in his head, while the army life would give him the ability to take charge and make things work. And then he takes on the family business. Which leads him to America, where the young master of a very old family is interested in running the manor that's been closed for so long.
The difference in temperaments between Grandfather and Grandson would be interesting, plus the responsibilities their feel to their respective families, to the secrets and lies and dramas they see, and in the end the difference between their times and duties and the way they grow to commit so wholeheartedly to securing other people's lives.