I still think your better legal solution is just to have Ukyou marry
Nabiki on paper, using the notion that Ukyou is legally male.

Also, I'd have thought everybody would be angling to unify themselves
under the Tendo last name, i.e. have the Ranma-Akane marriage change
Ranma's surname rather than Akane's.  Then an Ukyou-Nabiki marriage
can make Ukyou a Tendo also, leaving only Shampoo a non-Tendo.

Reminder:  given how common abortion is in Japan, you have to justify
Akane, Ukyou, and Nabiki NOT having them done (if that's your intent).

I liked the battle sequence.  I couldn't figure out at first why Ranma
would need to start out so apparently violent, but the explanation that
the sleep shiatsu only works when the opponent is distracted or calm
both made the battle scene more dramatic, and appropriately weakens
the technique.  It surprised me a bit that Kasumi would remember such
violent techniques when Nabiki doesn't (though I liked the idea of Kasumi
suddenly delivering that kick to Ranma).  I'd also hoped to see
Nabiki use strategy to better effect than she did.

Ranma actually showed strategic sense in addition to tactical in this
fight, which shows he's growing.

Kasumi sighed.  "Oh my.  I hope Ranma-kun doesn't get to badly hurt."

I'd have thought that Kasumi would have dropped the -kun by now.
Also, that "to" should be "too".

hkmiller