I would think there is no point in toddler formula if she is still getting boobie milk.

It sounds like it is mostly what other people are saying that is worrying you. The thing about being too weak to wake at night sounds like complete rubbish! I would expect serious health issues before that happened.

My DD doesn't eat much and never has. I always just kept an eye on her weight.

I reckon if you have a bub who is sleeping at night, happy and putting on weight then everything is fine.