بسم الله الرحمن الرحيم
Your mother-in-law can go with you for hajj. And if your sister-in-law has reached the age of marriage then find her a suitable proposal and marry her immediately so that she could go to her husband’s home. And if it is not possible then leave her to some relatives where she could stay with chastity and could live in purdah from non-mahram males.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.