I doubt the figures for Lahore, as there is tendency among urban Punjabis to claim Urdu as there first language. And secondly, what are the percentages, how much of Lahore is Urdu speaking. I have several relatives in Multan, and Muhajirs occupy distinct neighbourhoods.
As far as I know, Lahore is one of the most homegenous cities in South Asia, so need for Bal Thakray or Shiv Sena like organization. My wife is Lahori Punjabi, of mixed Kashmiri and Arain background. My Susrali tell me even caste wise, its mainly Kashmiri (Butt Mir etc) and Arain (Chaudhary & Mian). Both these castes ape the Muhajir culture, teach there kids Urdu, eat Paan and listen to ghazals. My wife speaks better Urdu then me. I suspect a lot of the Urdu speakers in Lahore belong these communities.