Hello blue lemon tree, huge fan of your bones and rubies theory. I'm not sure if anyone has brought this up yet but just in case this wasn't discussed yet here goes: do you think Alayne's dancing is a give away of her upbringing as nobility? I mean, realistically speaking, how good of a dancer could a girl from a religious orphanage be? And who might pick up on it? Thank you for your insight!
No, I don’t think dancing will have anything to do with that. Alayne’s cover story is that her mother was a woman of status, refined, and wealthy in her own right.
“...Your mother was a gentlewoman of Braavos, daughter of a merchant prince. We met in Gulltown when I had charge of the port. She died giving you birth, and entrusted you to the Faith. I have some devotional books you can look over. Learn to quote from them. Nothing discourages unwanted questions as much as a flow of pious bleating. In any case, at your flowering you decided you did not wish to be a septa and wrote to me. That was the first I knew of your existence." -- Sansa VI, ASOS.
Speaking as if this backstory were real, Alayne’s mother can afford to make a sufficient donation to the motherhouse in Gulltown in exchange for her daughter’s care, education, and proper upbringing. I can’t find any reference to them being used as orphanages. (There really is no official institution for housing orphans in Westeros. We can see orphans are pretty much S.O.L. and are left to fend for themselves.)
There are examples of septas who were from noble families, including some Targaryen princesses. Lady Smallwood says her great aunt is the septa of a motherhouse in Oldtown. That is where she sent her daughter Carellen Smallwood to ride out the Wot5K in safety. So becoming a septa is a perfectly acceptable occupation for a noble girl and an honor to her family. Some may reside in monastic life, but we can see septas play a major role in secular life as well.
Some families opt to bring a septa in-house to school their daughters in matters of the Faith and, most importantly, in social success. The Starks have Septa Mordane. The Tyrells have Septa Nysterica. Brienne had Septa Roelle. They impart their charges with an air of cultured refinement and high moral character, which is great for landing your daughter a favorable marriage contract. They teach girls courtesy and how to navigate through society for the family’s interests. They act as chaperones in social engagements to guard the young lady’s honor. They also participate in those same social activities. Dancing, as a primary form of entertainment among all classes, would hardly be frowned upon or ignored. By extension, then, a motherhouse can also be used as a combination of a Catholic boarding school and a finishing school if, for some reason, the girl can’t be trained at home as in Alayne’s case.
All Alayne's wealthy mother did was buy her bastard daughter a big leg up in life that she normally wouldn’t have in Westeros. She’s educated. She’s kept her chastity. She’s been trained in the ways of upper-class society. She had the option of a career as a septa if she chose to upon her flowering. It’s not weird in the least that Alayne Stone can dance if she also knows how to comport herself in other areas. At least that’s something that can help mitigate some of the bastard stigma.
George never goes into much detail about describing the dancing nor how people learn without necessarily having access to a dancing master, but apparently, they do. Perhaps one can simply follow along easily enough to be considered acceptable at it, so I would just take it as a given.
The passage about Alayne dancing is really meant to show us that Sansa’s love of dancing is still very much alive and well. It’s something that makes her feel good even in stressful, unpleasant situations, like at her wedding reception. That part of her true identity cannot be suppressed; however, she just hadn’t decided until that moment if Alayne also loves to dance, not that she can or can’t.