I have decided that the Savoulain expy's name is Nathan, short for Nathaniel. except that whenever the good doctor refers to him it's with his full first name and a not-entirely-fair amount of exasperation. the letters he writes back to Nathan are 10% insulting him, 20% insulting Summerset, 40% expounding on the evils of the upper class, and 30% deeply detailed and genuinely thoughtful answers to Nathan's questions and theories regarding the Correspondence. they are at least 5 pages long, not counting the books he sends alongside them.
Nathan's letters, meanwhile, never cease to be polite and kind, as if he's writing to a friend. he describes his own research on the scholarly paradigm of the Correspondence in great detail, from his theories to the everyday happenings of his studies. he engages with Dr. Ashveil's theories with both respect and curiosity, asking questions and probing weak points with no trace of malice. often he sends books of his own.
and the good doctor, of course, drops everything to reply whenever he gets a letter.
I have gone from "what if Nathan invited the good doctor to translate a box of sunlight with him" to "what if I wrote a whole thing in the style of an in-game storyline where you get to play queerplatonic matchmaker to these two"