#1 - May 19, 2018, 4:49 a.m.
Thank you Ythisens for clearing this up!
Pathfinder Part 1 will NOT require characters from different factions to complete it.
Link here:
https://us.battle.net/forums/en/wow/topic/20764426429?page=23#post-444
* Let's hope part 2 doesn't require it ;)