I think you need to separate out three things
- what you feel and think about the choices she has made
- what you can do about it now
- how to plan for the medium and long term with your daughter and potential grandchild
It’s ENTIRELY reasonable to be angry and worried sick about her future. I know you are getting a hard time here but I think most posters would share your anger, fear and worries, it’s mot the ideal that most of us would have planned for our 16 year old kids.
However, and it’s a big HOWEVER, there is fuck all that you can do about it . So there’s no point in throwing your weight around, arguing , trying to talk her out if it, moving back in etc. You can’t control her or her choices so you need to at least put on a good act of accepting it and supporting her. You will also need to be polite and reasonable with her BF, whether you like it or not.
The chances of this working out with her Bf are very low - everyone reading this knows that. So you need to working on rebuilding your relationship with her so that you can be there for her when it falls apart. @independentfriend has given you some great suggestions - you need to be very low key about it all, don’t try to boss her about. Respect her right to make her own her choices, even though you don’t like them.
Personally I’d NOT offer a lpt of financial suport and be buying expensive things for the baby. That’s the role for her and the baby’s father - they need to take responsibility. I think there’s too much focus on a baby as a consumer opportunity and not enough on the new mums physical and mental health ( but that’s just me ).
If you wade in buying expensive travel systems and £3K buggies, the baby’s father will feel pushed out. You want the opposite - him to step up. He’s not a child , he needs to take the lead here not you.
So Id be there for her when she wants it - yes meet up somewhere public, get to meet him, keep the conversation polite and low stakes. If you don’t , you could lose your daughter forever .