Aurangzeb has been historically considered a "wali" ("saint") by many Muslims. He was a pious devout of Islam, who during his last years use to write down the Qur'an as a religious act.
http://maktabah.org/blog/?p=2185
And the RSS can't even remove Jinnah's portrait from an Indian university, they'll take time to take down the +100 villages/towns named after Aurangzeb. They're only aiming for roads as of now.
I don't think he killed millions, you're giving him to much credit, probably the whole of Mughal killings. I think he restrained himself to 100 000s.
And yes, if it's proven that Lahore name is after some dead Hindu deity (again, it's just one of the many hypothesis), then yes Lahore should be renamed. Aurangabad would be a good option.
I mean cities like New Delhi, Lucknow, ... had Muslim minorities (even if ruling through force and coercion), not even majorities, and yet without Islamic culture these cities would look totally different, and probably wouldn't even have a reputation at all.
But Lahore is mainly Islamic and with some British/Sikh, I don't see how Hindu culture impacted it, despite the population. Perhaps one or two temples here. That was my point, that Hindu cultural impact on Lahore is limited despite the numbers. Also Lahore had no real culture before the Ghaznavid invasion in the 11-12th centuries, which pushed for Persian literary activities there, it's not an old-city like Multan let's say.
