Will I have internet coverage in the northern areas (Hunza, Gilgit-Baltistan, Skardu)?

It is very limited. You must set expectations correctly. You will have reliable 4G/LTE coverage in major cities (Lahore, Karachi, Islamabad). However, in the high mountains of Gilgit-Baltistan (Hunza, Skardu), only a special local provider (SCOM) works. Our eSIM (which uses national roamers like Jazz/Zong) will have little to no signal on the Karakoram Highway or in those remote valleys. This eSIM is for cities and main towns, not for deep northern treks.