as per details given by you my views are as follows-
1.daughters have all rights over the ancessostral property same as the son have on that property.
2.if your mother is not taken in process during the partition then she can challenge the partition or sale deed and even you can challenge it on the title of lrs of your mother.
3.my view is that your mother should file application for the partition of the property in issue,
4.nope,after the parttion the property can not become the self acquired property ,self acquired property is that property which is purchased and earned during the persons lifetime and with his earned money.
5.your grandfather and his bros and sis and children may be asked to record their stsaemnts regarding the partition matter whether they had accepted the following partition or not .feel freeto call if you had left any query