1-Lashkar e jangvi guys in Quetta are punjabis, you can confirm it from any quettawal.
2- Taliban in late 90s, didnt massacre hazaras in mazar shareef due to sect but due to revenge. First taliban captured mazar shareef but lost the city due to street fighting and sudden ambushes. Thousands of taliban prisoners were killed. When taliban re-took the city, they returned the favour. According to Afghan taliban claims, pakistanis of sipah e sahaba burnt iranian counselate in mazar shareef.
3- From what i have heard, there are no ethnic and sectarian tensions between pashtuns and hazaras. Afghan-pashtuns and hazaras are rather close with each other. Baloch nationalists have problems with both hazaras and afghan-pashtuns.
4- Most of the Afghan refugees in Quetta are not pashtuns but hazaras. Bulk of hazaras are illegal refugees. The ones with proper pakistani nationality, were settled here by british 100 years ago, in exchange for their military services against sunni balochs of iranian part of balochistan. @
Abu Zolfiqar would disagree with me.