The thing is you,your DH and you mother may decide various things for your children based on rationale and logic but your babies haven't got that rationale and logic. So far all your DD knows is that she loves her bottle but now she can't have it anymore and then you gave her a new toy and then you took it away. You are about to have another child. You want you DD to feel as loved and secure as possible. I don't think you are going the right way about it.
I was worried about DS's teeth too so used the green rigid Avent teat things instead of the soft ones. I seem to remember that they are better for teeth.
Your DH sounds a bit controlling about the toy and not wanting her to be spoilt. Your mother shouldn't actually get a vote on this. It's between you and your DH.
If you are aware that you were spoilt you can manage that your way. From my point of view giving babies toys is not spoiling. You can't really spoil a baby that way. Spoiling a child is more about giving them a sense of entitlement and teaching them to be selfish.
My DS is an only child and is now almost 10. He has lots of toys. Always has had. I refuse not to buy him stuff just in case anyone thinks he is spoiled. I did almost fall into that but a friend pointed out that I was actually going the other way and that there should be bonuses to not having siblings. And I know full well that he would much prefer the sibling to anything we could buy him.
So if you saw the 'things' DS has you may well think him spoilt. But he us not spoiled as a person. He is a kind and compassionate and mature boy who is mostly aware how lucky he is.
You can give a child lots of material objects and not spoil them the same way as you can spoil a child who doesn't have many material things but is not taught compassion etc.
And I dont think your DD has been shown much compassion on the whole bottle and toy subject.
I also get the feeling you are not entirely happy with the way things are going.