regarding therapy, something immensely valuable my wife and I stumbled on is working with a child psychologist who, rather than meeting directly with our children, does "parent training" sessions.
these takes the form of hour long meetings in which we relay a specific challenge we're having with one of our kids. Our therapist asks questions, offers suggestions, and reacts to different strategies we're currently trying.
it's been so helpful to have an objective third party who can offer kind feedback on approaches we're using, give us heads-up to potential fallout of certain strategies or reactions to difficult behavior, and also offer great suggestions on new or altered approaches to take based on our own family values.