could my wife and 2 years old son ( who was born in china ) get S2 visa

hello,

i am from Pakistan, 3 years ago i had x1 type, my wife got S2 type from chinese embassy in Pakistan, she stayed 6 months, now i have x2 type would you please help me to know that my wife and 2 years old son who was born in china can they get S2 type on my X2 type? or this is only allowed to X1 type or who has resident permit?
thank you so much