Happy belated bday. I don't have much to offer for advice, I think you're killing it on all fronts. Stay detached, keep busy and keep doing what you're doing with the kids.
Regarding om and the kids, sounds like that's going to be an emotional trigger for you. You've handled it well and you luckily got great people giving you great advice as there is very little you can do regarding the other camp. One thing I want to say and I think it goes along with what Sandi mentioned about giving the WW the one up and how it affects the kids' trust, is that you want to always be coming from a place of strength. The less you show ww and om the better imo.
Kudos for not accepting anything from the WW. You're right, she could be trying to extend the olive branch because she is getting what she wants and is feeling a little guilty but it doesn't change anything. It doesn't mean anything.
Keep your guard up and your wits about you as you move into the agreements on the D. So far it sounds like it's amicable, but its too early to tell. She sounds like she is getting what she wants but those little flare ups with the MIL and her calling your phone the way she did...(I'm a little suspect). I'd keep running everything through your attorney and keep your cards close to your chest. We don't know if om2 can become om3, etc...you don't know how bad it can get.
With young children involved with this transition, if you haven't already, have you thought about seeking professional guidance from a counselor. The reason I say this is because you mentioned the children asking where is om2 in your presence and correct me if I am wrong, you stayed silent, right? That could have been the best thing to do at that point but maybe it was brought up for a reason and in their own way they are trying to communicate with you. Its tough, I don't have answers to that but if I was in that situation I'd definitely seek some guidance on when its okay to talk to children and at what age. If they have questions, what is okay and not okay to say that is age appropriate. I'm sure they will want reassurance from you.
Also awesome job with you handling everything when ya'll were quarantined. I have 2 boys at home with a few scares over the last few weeks. I commend you because it's a lot of work keeping kids focused on their online learning, keeping up with the kid's missing assignments, and keeping them busy during quarantine.
H 49 , W 47 T 23, M 17 S11, S5 BD: 7/18 IHS: 7/18 - 3/19 Physically Separated: 3/19-4/19 Piecing: 4/19 - Current