The Indian, Pakistani and British leadership agreed upon the use of a plebiscite to resolve accessions of states that were disputed. This occurred in Junagadh and Hyderabad, and was specifically accepted in the case of Kashmir as well, and teh Indian leadership made clear statements that they woudl respect that agreement.
Then came the UNSC resolutions - the GoI agreed with and accepted the UNSC determination that Kashmir was disputed territory, and that a referendum in Kashmir was the means to resolve the issue. None of this applies to Baluchistan - Balochistan is not disputed territory. To bring Balochistan into this discussion is like bringing Tamil Nadu and Kerala into the discussion, and if you were even half-informed you would realize that.
Therefore both your arguments are invalid - India does indeed have an obligation to conduct a plebiscite, and there is no comparison with Baluchistan.
Again, if the living conditions in India and IK were really that much better than Pakistan and PK, the choice for the Kashmiris would be easy.