Are the spirit meddlers, despite their being used as weapons by the Extraterrestrial Alliance, actually working against the Alliance whenever they can, to increase negative emotional energy in their extraterrestrial hosts as they do with humans?

This is very true and a valuable insight you have had here. If you think about the spirit meddlers as the ultimate source of evil, why would they befriend any particular group of beings and serve them in any fashion to be of benefit? Their perspective, as you know, is always totally self-serving. The spirits look out for themselves. They only want more and more energy and they know it will come from causing emotional turbulence and this they will attempt to engineer by disrupting plans of their host and causing chaos. So they very much do this among the extraterrestrials over, and over, and over again, and work relentlessly to undermine them in the same way they do this with humans. This fits the picture if you think about the fact that the extraterrestrial beings plaguing the Earth have fallen so low and are so depraved, how could this not extend to themselves and one another, but only be directed outward at humans, and in other respects they are caring and respectful? That would be quite out of character. So the reality of things is the extraterrestrials are heavily corrupted with the dark spirit meddlers who also undermine them as they do human. They will obey direct orders from superior spirit interlopers who can exert power over them and cause them suffering, but that is no different than any group of prisoners being forced to do something with the threat of punishment as the motivation. This is a kind of defacto cooperation, in actuality, because they themselves will benefit from causing harm to their host up to the point the host is killed. At that juncture, they will have to scramble to find another host, which at a minimum, is an inconvenience, but can set them up for great difficulty as well if they are not successful in a timely fashion. So their preference is not to cause death, but they will do things when told, to ramp things to that level, and this may well happen because there are always threats levied against them by their overseers, and they do not want to be punished for disobeying commands from a superior force. This is the leverage the extraterrestrial spirits can bring to bear and why this recruitment and weaponization of the spirit meddlers is effective.