Seems I have already alienated some.
I have done it differently, with 5 babies no less, and ended up with 5 well adjusted, happy etc., etc. I couldn't get the hang of a sling, but did a lot of carrying of one particular DD in a back carrier. The younger babies did most of their afternoon napping in the car as I schlepped the older ones to various activities they did after school. I often carpooled so that five mums weren't dragging 15 uninvolved youngsters all over town all afternoon to activities. It was a good experience for the older DCs to use their manners, be ready on time when the lift arrived, follow someone else's car rules. Adjustment was the name of the game, for all.
All the older DCs learned to wait a bit for my attention, to entertain themselves and play together, and I became much more organised so that the amount of attention I could give them was maximised when the baby was asleep. I don't think it's a healthy message to give to older children that the household revolves around them, their schedules, their lives. Becoming more independent from their mum and developing competence at self-care is one of the primary developmental tasks of children from toddlerhood on. Babies are, by contrast, in total dependence mode.
No, the older children didn't choose to have the baby, but are they such pfbs that they can't adjust a bit when the baby arrives? From a developmental pov, it's much more important for them to learn patience and self-reliance than it is for the baby. They are both in school after all, not toddlers, and there's no question of juggling the almost equally insistent needs of twins and a newborn as MilaMae did. Why try to treat the oldest DCs as if they were the only children?
'A new baby wants to fit in, but it takes time for them to learn how.' Where does this idea come from? This is codswallop.
Nowherewoman, astute comment there.