Sorry to send a question when you are busy but I wanted to make sure I didn't lose where I had written it down but in a AU of reversal where only one of them is a girl would it be harder than in reversal for them where both of them changed as one of them remained male?
I also thought maybe Joffrey Arryn Jeyne Arryn preferred heir as an option particularly for Rhaella as they could both stay together and Cregan would be great for Aemma as there is the connection with the Starks and Jon's original life and heritage while Aegon and Aemond are themselves, will be usurper and kinslayers and are not nice people at all and not at all Oscar's fault but he is related to Catelyn Tully and that would understandably be an issue for Jon when he as Aemma or Rhaegar as Rhaella married him. Regarding the Lannisters it's not just the sack but during the Dance under Hightower allowance they stole half the Royal treasury and there is no evidence they gave it back so like with the Hightowers including Alicent children I can't see Jon or Rhaegar liking them or the Peakes due to poor Jaehaera and the way Unwin treated Aegon III sorry for the rambling
I've chatted a bit in the past about the challenges of one of the twins getting genderflipped but not the other. (TL;DR: Rhaegar almost certainly falls for his/her twin and assumes they'll wed so that they'll never be separated, leading to huge awkwardness for Jon, who has to gently break his/her heart.) There's a NYE prompt fill related to that, in fact, where f!Rhaegar shuts down a Green match by basically saying "don't be silly, I'm marrying Jon."
Going back to the Reversal!twins, though...
Rhaella: She's just as dragon-obsessed as Rhaegar and would ultimately want to be near dragons as much as possible, meaning she would either want to live in Runestone with Aemma or have a match that would allow her to spend a lot of time in Dragonstone or King's Landing (which means Jace is her ideal match, tbh, minus the queen part that she doesn't love). An Arryn match could work, but I could see Daemon vehemently objecting due to the Vale shenanigans that led to the girls being hidden away to begin with (aka don't reward the houses of the Vale). I could see a Velaryon match fitting the bill, as Driftmark is very close to Dragonstone and King's Landing.
Aemma: I think Aemma's personal ideal match is a second or third son, rather than a first son like Cregan. The logistics of both husband and wife ruling two holdfasts is difficult, even with the magic of dragonflight. Cregan would want his wife to live in Winterfell. Aemma wants autonomy/independence to rule Runestone. Ironically, a match like Rhea's (to Daemon, a prince and a second son) fits the bill. But since she's already a Targaryen and has a dragon, she's not as limited in her options as Rhea was. (Rhea's father basically wanted the match with Daemon to ensure that none of the Vale lords dared challenge her rule.) TBH, I don't think a Tully is a dealbreaker for Aemma. Cat was one person, and she can compartmentalize. It would mainly be the first son vs second/third son issue.
