Balochistan has little to do with India as some separatist wanted to be independent. Unlike Hyderabad and Junagadh which had the similar issue as Kashmir with majority of the populace a certain religion, but the ruler being different. Still, perhaps they didn't have anything to do directly to do with Kashmir, but the same principle must be followed in a court of law. The strategic point you mention holds no ground, as Pakistan could say the same thing for Kashmir.
Also, you conveniently forget that the Muslim majority populace wanted to side with Pakistan and in response to the Maharaj's indecision, they revolted. After which the massacres against Muslims started which fueled the fire and led to the revolution. After this, Pakistan army joined in to the war. It's the same situation as in 1971 when India joined the war when they had no right to.
And yes, the majority of the populace wanted to side with Pakistan, hence the revolt to begin with.
I already discussed that Hybd. Junagadh and Balochistan are done and dusted with. Kashmir on the other hand is still a disputed territory especially with the 3 odd wars taken place due to it.
They held a plebiscite for Junagadh back in the day, but didn't for Kashmir a state they were likely going to lose if they did. How convenient for India. The right thing to do today would be to hold a plebiscite now but of course the Indians will never do that. They'd much rather illegally occupy the land.