I dont think transport will be forced to go through lahore if eastern rout is being followed. M2 and M3 can be used to bypass lahore for traffic coming from Islamabad. Also the textile industries of faisalabd are dispersed across the lahore faisalabd highway. The nearest textiles mill to lahore from faisalabd textile group is around 40 km from lahore on lahore - faisalabad highway. Alot of textile mills have administrative units in lahore as well.
Nestlé, millat tractors, atlas honda and different steel mills are around 25 km from lahore on faisalabad road.