If you think unfriending will cause additional drama AND you're trying to keep the door open, Unfollow them. You won't see posts unless you go to their page to look. Also, you can customize your posts to hide whatever you don't wish to share. 

having put in a boundary - but with a door open (by their dad as well) where we have said 'hey, we want a relationship with you but we really can't do it unless we go to a mediator with you and discuss unresolved things - or even just how to move forward. You can choose the mediator, we can do it on zoom if preferred and we will pay.' 
 

Souds like a reasonable boundary to me

Sometimes so much stuff has gone down, there's so much to unpack and it's very difficult to do so without a professional 

They chose not to do that - with some form of retaliation such as 'so every time we have an argument we have to go to mediation?'.

Until they learn healthy communication......yes!

the SK we suggested mediation with has now had a baby. They have blocked us on FB (and other) from the announcement of the birth and all the details - but we get some scarce information. We believe it is punishment

Probably is a petty passive aggressive behavior 

Lot of mentally unstable people use their offspring as pawns.
 

"Hey if you don't do x,y,z for me then you will never see these kids" ...

Just as easy it is for them to attempt to manipulate you so be just as easy to replace them/their spawns with someone else who has kids but more respectful behavior 

You shouldn't have to be emotionally blackmailed by unsavory stepkids, their uterus, or their spawns 

When it comes to Facebook just know its messy and for me personally I prefer to block people. 90% of the time they have too much social media attention seeking to know you blocked them and if you change your mind bc they acting right you can simply unblock.
 

If you unfollow, they will know rather quickly because you'll pop up in their "friends you might know" section (leaving them putting two and two together like 'hmm I thought we were friends?') and if you change your mind you will be at their mercy to re-friend you  

So while blocking sounds more harsh it's actually better for moving in silence and easier to un-do if you change your mind  

They want to cause drama in your life. For screwing up there lives..  parents didn't do it by divorce each other. You and there father screwed up there life.  So now they in all good faith and style will screw up the GK.   BLOCK her,  blocking on Al, Facebook type of accounts is part of disengagement.  You are being disrespected, ..face that fact.  Unless you bend over and kiss there ass. ,.. you will be a outsider.   All they want is you and your SO to fight over them.   Just totally disengage...  who cares about there life. There GK, there problems.. you don't 

Unfriend them. Block them.  They made a choice to not participate in healing the relationship.  They are hoping to hurt you by trickling info.  Don't give them that opportunity.   If DH want to stay connected that's on him but you as stepmom CAN disconnect from them.  I have some of mine blocked.   I have BM and her flying monkeys blocked.  I chose to protect myself.  FB is toxic anyways. Limit it for yourself.  

depends on how much access you really are comfortable giving to the skids. Depends on how you feel about that situation. If you feel the need to unfriend or block or both, thats your call. As long as you understand that you are not obligated to grant them more access and availabilirty than you want to. No more than if they were anyone else if you feel thats whats best for yoiu.  And yes the emotional manipulation is all too real,, especially once the SKIDS regenerate...easier said that done but dont feed into that as much as you can. Take it from me, in some cases, they willl used whatever they can as leverage hence the guilt trip method 

KISS

Block them and stop giving them space in your head.

Their loss.

Good riddance.

People like your Skid(s) don't traise decent offspring so you aren't missing out on anything of note on that either.

Take care of you and your marriage.

I don't know much about FaceBook. So, if you just unfollow them, they don't know that you've done that, correct? But, if you unfriend them, they know that you've unfriended them?

I would unfriend them. Right now, they feel that they have all of the power when it comes to the relationship and the info they do or don't want to share. I would take that power away and let them know that YOU have made the decision to not get their trickles through FB, at their whims. If they want a real relationship, they can reach out in a real way.

I have unfollowed skids and have my FB default audience set to not include them, so there is zero FB interaction between us and I am no longer witness to BPD Mommy Praise posts while their FB world is led to believe that skids were the products of virgin births. I, too, considered unfriending but do believe that would create unnecessary drama. 
I have heard this end of conversations between SS and DH and DH is saying, "Yea, she posted the pictures," leading SS to go look. And I silently smirk. 

At the very least, unfollow. That's what I did with my SD. I got tired of seeing her passive aggressively lash out at DH and me for allegedly not spending enough time with her kids. 

Problem solved. 

And it feels great. I don't have to see any of her online drama anymore. So worth it!

That's why we are here.  We all been through this,  I was before Facebook. So I wasn't unfriend.  Just not takkeh too.  I look at it two ways,  I feel bad for SD, who no matter how bad I was, she wasn't sleeping in a car, had name clothing,  food , vacations.  It's her lost.   She is not mine, there's no guilt 

Unfollow.

then unfriend 

BOTH skids are blocked on my social media.

I've restricted my FB page. Only my friends can see what I post but anyone can contact me. I have a SIL that I can barely stand. She's an interfering busybody who has ensured I felt like an outsider and an immigrant. She's a card-carrying National Front (under whatever version happens to be their current mutation). I accepted her as a "friend" to not have to bother with the histrionics but refuse to subject myself to her racist diatribes soooo anything I post is visible to my real friends and she's excluded. I don't have time for that crap. Anyway,  she seems to have cottoned on to this because she seems to have done the same thing back. YAY! I am no longer subjected to the hate she spews. Win-win all round. 

I feel like it's pointless to even friend people a this point. 
 

 just follow / unfollow on FB and no one bats an eyelash 

Friending people is messy bc once the relationship goes sour "unfriending" just confirms and solidifies the messiness that most likely can/will occur. 

also make sure to make your friend list private on fb to cut down on the fb sleuthing/messiness

If you and daddy want to know something, ask directly.  That does two primary things.  It is an affirmative connection attempt, and... it puts the onus of an answer or not aswering directly on them.  

It is far harder to ignore a question posed directly to the individual than to ignore or manipulate on social media.

We always know when something is up with our kid. His rare communication grows far less frequent.  So, we call and ask directly.  At that point, we tend to get updates fairly directly.