Does Harbinger's ability combo with other effects that allow you to cast minions, e.g. Elder Ruins, Troubled Town, Peculiar Port, etc.?
Yes! It's effectively a passive ability that can be used whenever you cast a spell on your turn. The golden rule, baby!
When I determine my three random squares, what if I roll doubles or triples?
Reroll any duplicated results until you have three unique squares.
