WOW
Your Goddaughter doesn't have a chance. Not of achieving decent A levels and further education. She can do that, whether next year or in time.
But of growing up and getting to a place where she is a decent mum and has a good relationship with her own mum.
You seriously think telling your goddaughter that she will be a Crap mum and needs to live with you to continue her education (which is what you are all thinking about doing - suggesting to a mum that she can't/shouldn't raise her own baby or that it isn't really that important that she does so) is in her long term best interests?
Yes, your goddaughter could possibly do A levels at grammar school next year with good support from school and parents/grandparents (though I would have struggled to do a levels alongside DD1 when I was quite a bit older). What you are suggesting/doing is not good support from parents, it's extremely overbearing and pressurising. She would come home on Friday night after five days away and have to watch her mum play mummy to her DD and her DD consider another person her DD's mum? And get good grades or giving up her first year with her DD will be a waste. That is cruel, tbh.
Your goddaughter has chosen to keep a baby, so on some level she does want to be mum. She probably is in denial right now - it is scary. Don't strip this away from her under the guise of wanting her to do well at her education. Support her TO BE THE MUM, not replace her with another more acceptable (to you all) one and try to shoehorn her back in to the same place she was in.
Lockdown was tough for many many teens. But you are all in denial. Your GD missed social interactions and routine of school and fell in with an unsuitable boy, yes, but she also clearly also struggled with studying on her own and has a few issues with her mum (hence why you are suggesting she lives with you) - your proposal that she completes grammar school is likely to mean either more study at home around a baby that seems very close to the situation she couldn't cope with in lockdown OR a non-mum relationship with her baby that she may come to regret (and hate you all).
You know what, I went to a prestigious university at 18. I wish I had gone later, after resolving some mental health issues related to my autism - a more grown up me would have found it easier to adjust to a new learning environment. Studying a bit later (not just a year later) really isn't the end of the world. And nor is going to university - lots of great apprenticeships out there that get you to the same place whilst earning money and not accruing debt.
Back off - make a loose plan if she feels she can study around a baby next year. That's why FE college might be useful - it is more flexible and can be picked up when ready - it isn't a slight on her intelligence. Then try to support her for the Mum bit. That is the important bit. For her AND the baby (who you appear not to have considered fully - it isn't just a question of whether your friend is likely to be an objectively better mum than her DD, but that baby's interests in having the best possible relationship with her actual mother).