Why didn't Brya clone Akane?
Ahs is a dumb machine. The "cloning" in fact dumbly copy-pastes a chunk of spacetime, creating a really perfect clone of a person unless some measures are taken. Excluding some areas in the brain is easy (specific molecules in a specific volume), as Brya did to avoid creating a second sentient Ranma. More complex manipulations are out, there is no frame of reference to create formulas nor interface for it.
So all he would achieve would be two identical Akanes cut in half.
Ranma's hair going silver makes me wonder if she's the duplicate.
Were she a a proper unaltered duplicate, there would be no way to tell who is who. It copies basically atom by atom. They'd probably share the same soul, but going by Rumiko Takahashi, two people sharing the same soul could coexist just fine (see Kagome/Kikyo)
No, it's a known fact that even children had their hair turning gray during WW2 due to unimaginable grief and mental trauma.
Ranma is much sturdier mentally, yes, but the effect multiplied by the factor of a runaway Shishi Hokou Dan.
Basically, he channeled so much grief it should have left him scarred for life, a broken wreck. But all it did was leaving some trauma plus damaging his hair.
P.S. I think maybe I should make it white or gray, not silvery-gray. This would be less ambiguous. Kind of like Lina Inverse when she overexerted herself.
Awww was hoping for more of a "mad scientist" conversation between Brya and Ami.
Alas. I didn't want to bloat it even more, but in the next world the pinky would be met with as much friendliness and tolerance as a Nazi in Israel.
Don't worry, I plan much mad science and similar fun for her... In the sequel.