Re: Pressure to "stretch out" feedings......
Your friend is wrong. Wrong, wrong, WRONG.
And you are right. Crying is a late hunger cue. Allowing a baby to reach that frantic screaming stage is cruel. Give your baby time and he will eventually space out his meals all by himself. Feeding on demand during the day is probably the reason why your baby is sleeping through at night, since he's getting enough calories during the day.
Breastfeeding will not teach your baby bad eating habits or make him into a fat child. The American Academy of Pediatrics recommends feeding on demand as the way to go for breastfed babies, and says that to do otherwise is dangerous to the baby. (You can read the AAP media alert on the subject here.) There are actually a fair number of scientific studies that find that breastfed babies are less likely to become obese than formula-fed babies. (Here is an abstract from the prestigious medical journal The Lancet as an example. There are many more.)
I don't know if there's scientific evidence for it, but I suspect that scheduled feedings are more likely to ingrain poor eating habits than demand feedings. Think about it: if you starve yourself for a long time and then sit down to a meal, you're a lot more likely to gorge yourself than if you ate sensibly when hungry, right?
The next time your friend pressures you on this subject, you might want to look at her and say "My baby is happy and I'm happy. I see no reason to change what we're doing. I appreciate your advice, but I disagree with it. So let's not discuss this any more."
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"