Hi Claire, you've got a lot of good responses but I'll just add my own experience. FYI, I'm in Canada so some of the procedures and terms might be a bit different.
I had a scheduled c-section 4.5 months ago when my little one was 38+6 weeks. He was born at 7lbs 4oz and I had an otherwise healthy pregnancy (I've been T1 for 20 years).
1) My endocrinologist wanted me to go on a sliding scale for the c-section, but I made the decision with my OB to use my pump. My endo and I determined my post-pregnancy rates 2 weeks before I delivered and I programmed them into my pump ahead of time. I actually dropped them more than she suggested, probably close to 50% total drop.
I changed to the new, lower rates, the morning I woke up for the section around 8AM.
The surgical team knew I was wearing a pump and I put the infusion set in my back and kept the pump clipped to the very top of my gown. My section was at 11:30AM and my OB told me I could drink clear fluids if I went low in the hours beforehand (wasn't necessary). I tested my bloodsugar probably every 20 minutes or so because I was so nervous about going low.
When they put the spinal in, and it started to take effect the sensation in my body reminded me of being low so they gave me something to slow my heart rate and let me test again. Every time I tested I was fine. My husband held the meter after they let him in the OR.
2) I was far enough along steroids weren't necessary.
3) I was not able to successfully breastfeed. I have flat nipples so he couldn't latch anyway, but my milk took 4 days to come in. Baby had low bloodsugar as soon as I delivered so he needed formula ASAP, which my husband gave him. I had a bad reaction to the spinal (I'd never had anesthesia before) and was very sick, nauseous, and throwing up for about 12 hours after. I barely held the baby but honestly didn't care because I was so out of it and needed to keep checking my own sugars.
The hospital had pumps, and I did try to use them, but I was only ever able to get 1ml of colostrum, and nothing else came out. Baby had low bloodsugars so we ended up staying in hospital for 4 days and had to feed him formula every 2-3 hours and the nurses had to test his sugar before every single feed.
I ended up exclusively pumping and just stopped 2 weeks ago. Honestly, I didn't find pumping to be too bad and will probably do it with future children. I used a double electric and was able to keep up with babies supply for the most part and supplemented with formula otherwise. It was nice having my husband be able to do night feeds right from the start.
4) The day of the section, my sugars were perfect. The days after, I was low like crazy. I put granola bars, dex tabs, and juice boxes all over my house and I brought tons to the hospital and went through most of it. Every day after the section for about a week I had to keep lowering my basal rates.
Sorry for the wall of text - let me know if you have any other specific questions. Good luck!