If the “center collapses” and the ruling Anunnaki dynasty loses power, will the Reptilians and Arcturians turn on them, accelerating their destruction at this point of great vulnerability?

There is always some potential for war among the members of the Extraterrestrial Alliance, but this is not likely at the present time. There are more pressing concerns about managing humans themselves. The Alliance is getting along and there is a plan brewing to create a kind of equity sharing that would make a transition to a humanless world to not be a trigger for war.