Indirectly mastani baki ki sister ho hi gayi thi coz Chatrasal consider baji as his 3 son as per some people , that's why I have this question dint chatrasal knew baji is Brahmin & her daughter will face so many problems.
Baji was politically ambitious chatrasal gave him 4 provinces amoung that baji annexed zansi to Maratha Empire after chatrasal's death he immediately took control of zansi , further chatrasal gave assurance of bundelkhand rajput assisting marathas in northern expentitions ,as well 5 hundred gold coins & other stuff who will let go such an offer ?
I guess either chatrasal kept this condition untill baji accept mastani political alliance won't form aisa kuch as in one of historian ninad bedekar speech he tells baji said to chatrasal it's enough what u gave me I don't want anymore I don't want mastani , in return chatrasal said no u have to accept her , so ek tarah se mastani thopi gayi thi Bajirao pe . Many historians including yadunath sarkar says Bajirao dint brought mastani with him she was sent later .
Yes kashibai belong to very rich family of chaskaman her maiden house that time was of 4 storey , her family was chief funder of maratha army & her father was royal treasurer.