Update

How are things going? I hear that a lot. The answer is complicated. Over all... much better than we ever had a right to hope for. Yenenesh and Melese seem like they want to be a part of our family, and they like us. That is huge. Not all kids want to be in a family at first.
The tantrums have gotten better for the most part. There are some big blow ups... one memorable visit to the park ended with one child (who shall remain nameless) being hauled like a sack of potatoes over Nathan's shoulder for the entire four blocks home, kicking and screaming the entire way (this was after the ten minutes of being collapsed like a puddle in the middle of the playground because he or she wanted to be the only one in the wagon instead of sharing it with siblings). These types of tantrums have really gotten few and far between, though. The competition and aggressive neediness is easing up a little. We have learned to usually take turns and share. Some things are still hard.
It is hard for Mer to share us. To not have 100% of us. That breaks my heart. I see her being sad sometimes, and I feel terribly guilty. But she also has a lot of fun. She loves having people to play with and seems genuinely glad to have a brother and sister. She is maturing in ways I kind of wish she didn't have to... but I have always had issues with wanting her to stay a baby forever. I just wish it was a little more on her terms instead of necessity.
But overall, we're okay. Great. Miles ahead of where we were even two weeks ago. And it is getting better all the time.