Wow jwashing, you seem to be very ambitious. Every other post you start deals with going to law school, med schools, careers, law firms, LSAT, etc…
I wish you the best of luck, hatzlacha, in everything!
I don’t know of all the big law firms, but I will say that work/family balance is probably very tough for young associates. I don’t believe you can be discriminated against for keeping Shabbos and Yom Tov, but you have to make up the work later to get those billable hours.
Also, unless you have pull, you would need to go to a top law school and get top grades to go to the biggest firms.