Their building of any bunglow/palace or anything on the land will have no effect on your rights as a coparcenar. Your rights exist independent of such construction, though, no denying such decisions should be made by all coparcenars since the property is hotpotch and bested birth rights of all.
--Third, the suit has to be filed in Rajasthan as the property in issue is under the jurisdiction of the same.
--Second, you ought to have property documents in hand to file a suit as far as i Think. Shall confirm you once again.
--First, see adoption should be on papers and should be registered as per sec 16 of HAMA, 1956. Eventually meaning having legal status as a child to the adoptive father. It is strange he is still following his father's name (not complete as to meaning to be adopted) and not your uncle's. His status as been adopted is suspicious. But also to remember the onus whether the adoption is valid/invalid is onto the one who questions it (us).