Badlands and "Flame's Fury" respect limits on "What could this Power have damaged?" This may include caps on the number of Invaders being Damaged, or specification of exactly which Invader(s) are to be damaged.
Damage from a single effect is done simultaneously. For instance, with the threshold effect of Dissolve the Bonds of Kinship, a City, a Town, and 5 Explorers can wipe each other out.
So if you had a City, a Town, and an Explorer all with Strife, the Town + Explorer could destroy the City while the City destroyed the Town + Explorer.
Both Serene Waters and Roiling Waters can only be claimed as a first Healing Card, and both Waters Renew and Waters Taste of Ruin can only be claimed as a final Healing Card.