We split the night duties from the beginning. Many of my girlfriends proudly pointed out that they did the night duties because "my husband has to work". But my point was: I will be working in 3 months, so he might as well get used to it. It was very important for our relationship for us to be relatively equal here.
YMMV. It depends on your sleep habits. For example, I tend towards insomnia and an inability to go back to sleep.
With our first child, he would wake a few times a night. My husband would pick him up, and hold him upright until he pooped. Then he'd change the dirty diaper. And then my husband would go back to sleep. I would nurse, burp, and wrap like a burrito, and put him back to bed. So my husband would say "oh, it's not so bad, it's only 30 minutes." No. It's 30 minutes for YOU, it's 1.5 hours for ME, because I'm awake for 30 minutes and THEN it's 45 minutes of nursing, and THEN burping and burrito and bed.
If it's the opposite, and your partner has difficulty sleeping, then you might want to be nicer than I was. But my spouse falls asleep quickly.
Otherwise - if you are going to pump and use bottles at all, you generally will want to start between weeks 4 and 6. That is when you should have established a good nursing relationship AND the baby is young enough to handle change. Wait too long and the baby may refuse the bottle. Start too early and they may refuse the breast (and some babies have no such issues going back and forth. It's a crapshoot. I have friends whose babies refused the breast because they got the bottle too early and some who refused the bottle because they waited too long).
That means you *can* do the midnight swap feeding. For example, I have friends who did this. Mom would nurse at 9 pm and go to bed. Dad would do the midnight feeding with a bottle and go to bed, mom would do the 2 or 3 am feeding (nursing). That way they both would get a solid 5 hours. I know I started to miss sleep after several days without a single 5 hour stretch.
It wasn't hard for me to maintain a supply. Every morning I had an abundance, so after nursing I would pump the rest. I would also exclusively nurse when with my baby, so nights/ weekends. (I worked during the day). I would NOT pump "Just to pump" because it sucks (quite literally). But for example, it shouldn't be hard to pump in the mornings after nursing.
With the second baby, eh, I remember less. I do know the first couple of months it was 12 hour nights. I'd nurse the baby at 8, and go to sleep, and then wake up every few hours, and would finally "wake up" at 8 am. I don't remember following the same routine with diaper changes - baby #2 didn't poop on demand like baby #1. So more likely I would do the nursing, he'd poop, and then I'd change the diaper. However, baby #2 was in a cosleeper in our room for a few months and in our room in the crib for 10 months, much longer than baby #1. He also slept 9 hours from 3 months to 7 months, so way easier there, at least until teething.
