As far as I understand, the Muslim Liga and its leader Jinnah were prepared to discuss the possibility of a united India as long as it would be a state that secured minority rights, which could be done for instance by having a federal state and/or some sort of
consociational arrangement.
What factors would have to change in order to make this possible? What factors were most important for the actual outcome? Was it a lack or trust? Or perhaps personal ambitions?
OTL something along the lines of the Consociationalism existed in Lebanon. Didn't turn out too well for them.
Acceptance of Jinnah's fourteen points is critical to getting Jinnah's support. Or at least some of the fourteen points. Some points IMHO are just counter-productive.
More importantly we need to see why the fourteen points were essential in the first place. Muslims really were a threatened minority back in the early 1900. Their population back then was a lot smaller as a proportion compared to say 1947, let alone modern times.
Considering that back the sub-continent was a pretty divided place along every possible fault line thanks to almost 150 years of British 'divide and rule', it wouldn't be surprising if minorities, not just muslims were apprehensive of living in a a hindu-majority state. Even the rights of tribal people and the backward castes were pretty much a political non-issue, if it weren't for Ambedkar and Gandhi.
If in 2001, in the Godhra riots, people could be instigated to murder innocents in the name of religion, it wouldn't be surprising if that would have happened in 1900s.
Secondly, most muslims in the sub-continent and even today to some extent were poor. They were mostly tradesmen like tailors or butchers, etc. The mercantile class was mostly of Hindu traders. As such there was a possibility that they could have been exploited by politicians in the upper classes. Interestingly enough, if anyone knows anything about politics in both India and Pakistan, they will know that this happened anyways.
So it was natural that a palpable apprehension would remain among muslims, especially after Gandhi started appealing to the hindu majority later on to increase popular support for his movement.
As i had explained in your other thread Jinnah never really liked Gandhi, and in the beginning it had nothing to do with the Hindu-Muslim equation.
Perhaps if Gandhi died in the Boer War, and the moderate faction, which included Jinnah, survived and rose to prominence in the INC then it is very possible that sub-continent would not have been divided but would have been a united dominion sometime in the late 1930s and would have a constitution that strongly protected minority rights, just as the backwards castes and the tribals are protected in OTL india.
Hope this helps.