eigenspaceWit, unker, Git: The lost medieval pronouns of English intimacy
https://www.bbc.com/future/article/20260408-the-extinct-english-words-for-just-the-two-of-us
Also sad is the fact that “you” is now used for “thee” and “thou” and such. The older variants could distinguish between “you” plural and “you” singular
Before I moved to the South I (a non-Southerner) did not feel comfortable saying "y'all". But "you guys" seemed sexist. I have since spent a decade in the South and I have not picked up much of the dialect, but I definitely say "y'all" now.
"W'all" would be nice to have. I guess it's not a thing because it sounds too much like the things that separate rooms.
Have you yet progressed to y'all being singular and all y'all being plural?
No. As far as I can tell, singular "y'all", when it exists, is an implied plural. What you might hear as singular "y'all" is, say, when you go into a restaurant and say "do y'all have Coke?" to the server - that doesn't refer to just the server but to the restaurant as a whole. But I'm not a linguist and also I don't spend much time among people with heavier Southern dialect, so you shouldn't believe what I say.
No, you've got it right. A lot of people trying to be cute and make southern language seem more alien than it is are over-"correcting."
When southern people say y'all to one person, they're really addressing you and your family (even though you might be the only one there.) If I ask "how y'all doing?" I want to know how you and yours are doing.