Questions:
1. How can we find out what is the overall property the joint family owns given the secrecy being maintained?
Your wife has to personally gather the information about all the properties that are lying in her father's name and her uncle's name separately and jointly.
If the property fell into your father and his brother's hands by way of partition or proper inheritance then the character of ancestral property shall stand diminished or extinguished.
She has to gather the information of the property documents of the various properties that are yet to be partitioned, after obtaining the particulars of the document number she may obtain certified copy of the registered document, get EC of them and ascertain what is her entitlement out of them.
The problem that how she can obtain the documents is to be manged by her through her own sources.
2. How can we know what is being shared and given to each of the legal heirs?
This is an internal family affair which can be obtained through some reliable sources only and legally you cannot obtain the details if you dont have any details about them.
3. What sort of legal recourse we have, considering that repeated requests from my wife over the past year, have met with no responses on details.
If she is having the details of the property she should consult a local advocate, get the details of her entitlement in the said properties and then plan to issue a legal notice to all of them seeking her share by partition and separate possession subsequent to which she can file a partition suit seeking the said relief.