2. I have heard that formula is harder to digest, therefore can fill them for longer, and some babies can sleep better because of this. Then, if a mother choses to breastfeed, then is it perfectly normal for their babies to wake a few times in the night for a feed, and we have way too high expectation on our babies to sleep through, when they are only doing what nature had intended anyway?
I do believe we have too high an expectation on our babies to sleep through. People go around saying that babies should be sleeping through by 8 weeks, or at most 3 months. It's a load of rubbish. Many many babies don't sleep through for a couple of years (breastfed or formula) and it's completely normal! We still wake a couple of times a night. Actually very recently he's slept through from 10pm to maybe 7am, but that's only if he's in our bed, and he does wake and reach out to hold me and then goes back to sleep... doesn't always ask for a feed these days.

But don't beat yourself up over the times you let him cry a bit. We've had times where Tallon has carried on through the night, and I've just laid down with him and he cries for a while. Who knows what really is going through their little minds at night. All we can do is let them know we're there for them. They'll sleep through when they're ready, and it sounds like Cooper was ready to sleep through anyway