I dont know about Mumbai..but I heard there is a considerable population of gujaratis in mumbai who are vegetarians..these veg dont even get along with other non veg hindus let alone muslims.Can't have the other way even if they want to live in upscale housing in Mumbai, muslims can't buy, rent condos and good apts. in Mumbai in better areas like Worli, Bandra, south of Mumbai, other upscale areas...they end up living in Bhendi and Chor bazaar, Dongri and poor areas, isn't it so.
As for south india there are plenty of muslims living in hindu areas but you cant find many hindus in muslim aeeas.