Will the construction of a new mosque on a custodian land be allowed?

During the period of partition of India, some people left to the other part i.e. Pakistan leaving their property here particularly the land they owned. This land remained with Govt. under the title “CUSTODIAN LAND”. The land was later given to the people on hire/lease for 90 years etc. Now the issue is that: A person under whose occupation is such a land at present for last two generations as per Govt. hire/lease, wants to donate a portion of his original own land for the construction of mosque, but the location of his that original land is not suitable for the construction of mosque. Now the said person wants to donate, instead, a portion of Custodian Land that is suitable locality-wise for construction of the mosque and wants to interchange this portion with his original land which is adjacent to this custodian land i.e. he would now transfer the same portion of his original land to the custodian land, thereby the custodian land remains area-wise unchanged.
The question is now, “Whether the new mosque can be constructed on this portion of custodian land against which the occupant transfers same portion of his original land to the custodian land.” It is further to clarify that the whereabouts of the original migrant owner are not known who is told to be a Muslim, as the Muslims migrated from this area to Pakistan. The land is in Srinagar Jammu & Kashmir.