You're going thru a really painful time right now. For your own sake as well as the sake of the girls you must find a way to stop expecting your ex to do the things you want him to do. I urge you to get started with counseling. You deserve to have less stress in your life and the way you're reacting to your ex is creating even more stress than is necessary.
You cannot change him! You can only change the way you react to him. And you do that in part by the way you think and talk to yourself. When you're expecting him to show up on time, remind yourself that he never does and tell yourself to stop expecting him. Talk with yourself over and over about how he will not do as you expect.
The next step is to let go of the anger this creates. Ask yourself if you'd rather be right( by insisting he co-operate) or would you rather be happy (by expecting nothing.) It will take time for you to work this out. I urge you to get started now in changing the way you think and talk about your ex and his behavior.
I think you did the right thing by naming the baby your choice. I might perhaps have given him his father's choice as a second name but I understand if you didn't. He is not participating in the pregnancy and birth of this baby.
Plan on your ex always disappointing you and find a way to say, "oh, well, I know he's a jerk." and then let it go.
And please get some counseling to help support you during this really painful time. You deserve to have support. You can find support. You deserve to have a supportive husband but you don't have one and you can't make him into one.
If I remember correctly, you said you have very few friends and family to support you. The hospital will have a new mom and baby support group. I suggest that you join that so that you can perhaps make a friend or two with whom you can share baby stories.