I'm American and I moved the other direction to the UK 15 years ago. Never in a million years for all the money in the world would I move back to the US, sorry. All the reasons you cite for not wanting to live in the UK are leaps and bounds worse in the US. Crime, which has always been worse than the UK, has gotten precipitously worse in the US in recent years. I've lived in some dangerous places around the world and there are places I just wouldn't go in the US now.
Health care and food is awfully expensive. And access to health care, even though you are paying privately for it, is not great. Things have changed since the 'Obamacare' years, so it's better, I think, than when I lived there, but still not great. As much as people complain about the NHS, I've never had better access to health care as living in the UK (and I say this as someone with a background in health policy). I waited 2 years for a biopsy in the US and still had to pay $800 out of pocket for it. That's before you get to gun culture, right wing politics, Mike Pence running for president, lack of a social safety net or support for new parents or early years education. And the culture, the culture is very different. It would be a hard adjustment, even for me now.
On a more practical level, I would not bet on a green card. We looked into my dh moving to the US when we were exploring our options, and it was not necessarily straightforward or cheap.
But really, I wouldn't commit my children and I to living anywhere I'd never lived for life essentially. When I moved to the UK, I did it before we got married and had children. It meant I had several years to adjust and know that the UK was going to be my home forever before we had dc. Once you have dc and are settled in somewhere, it's so much harder/near impossible to go home if you split. Even if dh and I were to divorce now, my life is in the UK. My children are British. All my friends are here. I'd never move anywhere else, husband or no husband. But what happens if you hate it? Is he willing to move back? What if he won't? You and the dc probably wouldn't be able to go without him. What if you split up?
I think it's worth exploring, if you find you really can afford it, but I would go as a tourist on an ESTA for 3 months and not give up all your commitments here until you are certain it's for you. It's a big expensive, stressful move, and I only did it just moving myself, no dc yet.