so uzume know seals.
does naruto will be also prodigy with fuinjutsu like his father and an uzumaki is supposed to be.
Will you give him chakra chains and uzumaki clan bloodlines?
Or do you plan to keep his skills mostly canon, maybe just slightly better.
Hope for the first one, canon naruto skills really sucks and fail most of the time when kyuubi power is not involved.
If not, i will get out, since naruto with canon mostly skills, is not my kind of fic.

really hope you won't follow the usual orphan twin path with naruto twin being the skilled, smart one who likely awake some clan bloodline and naruto kept as the talentless clone spammer idiot who is nothing without kyuubi power and dumb luck.
But having naruto very soon awake all the fucking family-clan prodigy talent, intelligence and bloodlines he deserves (means fuinjutsu genius, chakra chain, several true elemental ninjutsu of differents affinities).
If not, just rename the fic "Uzumaki Yin twin" to not fowl the reader to believe naruto will be as important and skilled as his sister.

Ok so I'm assuming you named your OC twin Menma because that is what Naruto's name would have been in the alternate reality. My issue is that since I know Menma to be Naruto and to look like Naruto, I'm having a really hard time associating the name with your new OC. I have to consistently remind myself that Menma is a girl who looks like Kushina instead of a carbon copy of Naruto. It's always difficult to inject a new character into an already established story line and I think you're just making it harder on yourself by choosing that name. Additionally, Menma's personality is coming off a little too much exactly like Hinata. I get she supposed to be the Yin to Naruto's Yang i.e the quiet to his loud and the meek to his confident but I feel like instead of creating a new character you're really only taking characters that already exist and mashing them together. Anyway, besides that I think you're off to a good start.

Interesting. I like that you gave the female naruto twin the name Menma. Since she has the Yin version, I suspect she'll have more trouble getting rid of the negative emotions than Naruto did making her similar to Road to Ninja Menma. Also Menma Uchiha is pretty notorious in the fanfict community so I wonder if you'll ultimately make her a similar protege like him and pair her up with Sasuke.