Path of Mettle’s first ability deals 1 damage to each creature that doesn’t have any of the four listed abilities. It doesn’t deal 1 damage to each creature for each ability that creature doesn’t have.
For Path of Mettle’s last ability to trigger, any two attacking creatures you control need to each have any one of the four listed abilities. They don’t need to share one of those abilities. For example, attacking with Sun Sentinel (a creature with vigilance) and Fanatical Firebrand (a creature with haste) will cause Path of Mettle’s ability to trigger, as will attacking with two Sun Sentinels.