Have the companion animals—both dogs and cats—been genetically tampered with by extraterrestrials to indirectly harm humans by making the animals more sickly or to have undesirable behaviors?

This indeed is the case. So one can look with suspicion at any genetic defect that persists and is not a random-seeming event, but a breed characteristic that speaks to a mutation with a high degree of dominance that will be a clear problem and a recurrent liability. But just because the problem is there does not mean it cannot be healed. That is very much the case, and can be done by applying the Lightworker Healing Protocol to request healing for the genetic distortion and this will take care of the problem nicely.