Thanks for the update, Noregrets! I may be wrong, but I have a feeling you're right about the mediation call prompting the parents to initiate some contact. If they said yes to mediation, they might end up having to stick to an agreement about how often to let you see the GC. Or they would refuse to compromise and the case would end up in court. This way, they still retain some control over how much you see the kids, so that may make them feel better. And as long as they allow some visiting, I guess, they feel you can't make a visitation case. But, no matter, b/c you're getting to see the kids and keep an eye on things, so that's good.
Of course, you're right, they could end the contact at some point for whatever reason (or no reason). So I'm glad you got that certificate. Like you, I hope you don't have to use it.
I agree that all the children are hurt by this situation, no matter what role they play (scapegoat, Golden Child, or whatever). Fortunately, I've never been in an abusive situation, so I might not know whereof I speak, but I understand your feeling that one child may have it "worse" than the others. For example, if all the kids in a family were beaten every day, it would be harmful to them all, physically, mentally, and emotionally. But if one were also called cruel names while they were beaten, their experience might be "worse" in that sense. Or, oh, IDK, if one were frequently locked in a closet or maybe in a basement that, say, was full of cockroaches or rats (I'm making this up and probably not doing a very good job of it), they would probably have worse memories than the others, even nightmares, etc. So yes, they would have gone through a "worse" experience than the others, even though they are all hurt by just being in that atmosphere.
I admit, I'm not sure why you see IJ as a scapegoat and not the others who have been abused. But perhaps she tends to get blamed for things more than the others? Or??
As for the little guy, I'm sure you don't call him a "spy" to his face and are just saying that to us. It's sad that his siblings see him as that though. Does he see himself that way? How awful that the parents pit the kids against each other. No doubt, that's part of the abuse, as I think another poster indicated. Divide and conquer and control (sigh).
Regardless, you're the one who had the courage to step forward and report the abuse. And now SS is involved, and I trust, all the children will benefit. I wish you and those kids all the best!