I want to start by saying that this may be some very unpopular advice, and it may be hard for OP to read. Everything that follows is my opinion only, so please read it as such.
If the dog has already bitten a child twice, and one time the resulting wounds required stitches and the dog had to be held back from doing more damage, I don't think it should be placed with either a rescue group or in a shelter. Sadly, the dog should never be trusted with or around children again. It's too much of a risk. And neither a shelter nor a rescue group can 100% ensure that he won't be placed with someone who will ignore those risks. Which could result in the death of a child, if the dog is rehomed with someone who doesn't heed those warnings and is irresponsible.
I also think you will have exceeding difficulty finding a rescue group who will take a giant breed who has a history of biting children. Unless you lie to them about the severity of the bites, which would be irresponsible and beyond negligent. Any shelter will most likely euthanize him.
Unless the breeder will take him back, doesn't have kids and is responsible enough to keep him confined, I don't see a lot of options for you outside of humanely euthanizing him. If you don't feel safe with him around your children, then he's not safe for anyone's children. His aggressive behavior towards children has a escalated, and I believe it is irresponsible to place a dog who has bitten a child without provocation in any home, regardless if the home has children or not. Especially considering the nature of the attack, how he went after your daughter as if he didn't recognize her. That is unstable and unpredictable behavior.
What if Odin were to escape from his yard? Get loose on a walk? What if he attacked a child without an adult around to stop him? There are too many risks involved with a dog who has bitten a child to the point of the child needing stitches, in my opinion.
I don't say these words lightly. My late GSD/Dane mix, Loki, was child aggressive, and put a child in the hospital before I added him to my home. Granted, he was being hit with a stick and retaliated, but the boy needed over 40 stitches in his face and neck. Loki was dangerous, and required constant supervision, training and a lot of my time and effort. He was never safe around children, and several times I had close calls during which I was lucky he didn't attack someone's child. He was the most difficult and demanding dog I have ever dealt with, and if faced with rehoming him, I would have put him to sleep. No one else should have to deal with those types of issues and dangers, and most people are not experienced in the type of management a giant, unpredictable, child-aggressive dog requires.
Before the flame war starts, I say these things not because I wish to be cruel or insensitive, but because I think it's kinder to humanely euthanize an unstable and aggressive dog than to bounce the dog from shelter to foster to who knows where. The revolving door of environments and new owners usually only serves to aggravate an already unstable dog and is not generally a good rehabilitative environment for HA dogs, in particular.
I'm sorry you're in this situation and that you're faced with some hard choices, OP. I hope you can bring yourself to do the right thing, and that is, whatever you feel in your heart is the right thing to do, not what *I* think the right thing is. You are the one who has to live with your decision and its possible repercussions, so I hope you can find peace in your choices. I wish you luck throughout this process and I hope your daughter recovers quickly from her injury.
two suggestions. My sister has a dog who bit her kids multiple times and then her daughter's BF. She finally realized she had a big problem/liability. She sent the dog to intense training outside the home for two weeks. The trainer tested her, pushed her and trained her quite hard. Four years later and not one bite. Along with a well behaved dog. My sister new that if the trainer deemed her as aggressive and not a good candidate for rehabilitation the dog would be euthanized. 