Hi,
My sister is over 21 years old and married . She lives in Pakistan
I am US Citizen over 21 years and married. My Mother is US Permanent Resident. We want to apply green card my married sister is Pakistan .
Q1 :
Should I apply through me as US Citizen or should I wait for my Mom to become US Citizen (she have just obtained Green Card few months ago) and the apply for my sister. Which rout will take less time. All of us were born in Pakistan.

Q2 :
Once we have applied for her using any of the above method, can she still aply for other non-immigrant visas (visit visa) while her case is in progress.

Thank you

Q1. Well, right now, the wait for F4 category (sibling of U.S. citizen) is about 12.5 years. The wait for F3 (married child of U.S. citizen) is 10.75 years. Plus the 5+ years your mother will take to naturalize, it would seem that you petitioning directly for F4 would be faster. Of course, you can always do both to hedge your chances.

Q2. Yes.