Pl advice, what legal steps can be followed to get this dispute resolved?
If the property is lying intestate, you may file a partition suit seeking separate possession of your share in it. The legal case will make them to sit back and think.
Can the occupants have any upper hand in purchasing the property?
No. The occupants can be dragged out if an EP is filed after disposal of the partition suit.
If the matter is resolved legally, what options are available for its disposal/sale?
If the court decrees the partition, then the disposal details can be mutually agreed by the owners of the property.