Hello,
1) If the title was clear at the time that your mother purchased the property by paying the entire consideration and if the transfer was registered duly any subsequent claim as enumerated in your query can not bring about an encumbrance on the property.
2) If the divorced wife of he earlier owner filed a case against her former husband and if your mother had been made a party this would be a case of clear mis joinder of parties to the suit.
3) It would be necessary to peruse the details of the suit you have filed and the case of the contesting party to arrive at appropriate steps to be taken going forward.What was the need to have the original document submitted in the court? Documents only need to be verified as and when required by the court.