Ryoko will be about 7-8 months younger.
She'll stay not a ninja.
Joseibi will be about four years younger, roughly the age of Konohamaru brigade.
Incidentally, have the story up as "Chi and Chakra" right now
I'm definitely going a Naru/Hina thing, though.
I'm not sure for Ryoko, but I can see a couple of possibilities.