This is a difficult extract. The quote is an attempt at very high English but it contains errors and, in my opinion, is too wordy. 1. You are correct. The speaker is expressing that mothers expect the outcome of ''addiction" to the doll as a normal childhood occurrence or expected behavior. 2. This is a deceptively simple idiom. The horizon is where the sun comes up and far away things become visible. In this extract, "on the infant's horizon" means that it is newly visible along with perhaps an unlimited amount of other things as well. 3. You have captured the sense of this. The parents accept that the infant becomes aware of the doll but they are not bothered by it. Please feel encouraged that you understood this as well as you did, it is challenging. The speaker even used the very rare subjunctive mood, which is almost extinct in modern English. " As it WERE " looks like a conjugation mistake but is actually correct in this rare instance. Great job!