I had my son Micah at 35 weeks and my son Zephan at 31 weeks...
From what I remember, most babies do pretty well with breathing by 34 weeks. I think some apnea of prematurity is common through about 36 weeks. They may need a little extra oxygen, especially in the first day or two as they adjust to life outside the womb.
I agree that you should be prepared to pump breastmilk. Try to do this within the first 3 hours of giving birth. It might take a little longer for your milk to come in if you are pumping and not able to breastfeed, but be patient.
Most likely you will be able to hold your babies within the first day. I held our 35 weeker after maybe 8 hours and the 31 weeker after about 24.
Do kangaroo care as soon as you can! This will help your milk come in and will be very comforting to your babies.
You may be able to go straight to nippling...this really depends on your kids. With babies born after 34 weeks, I would ask to try putting them to the breast as soon as they are stable. My 35 weeker breastfed well from the first day. My 31 weeker had an NG tube for about 3 weeks. We began "practice" breastfeeds at 32 weeks and began measuring how much milk he drank at 33 weeks. By 33 1/2 weeks, he was able to take a little more than an ounce by breast, so we began to breastfeed him more and give him less milk through the NG tube. By about 34 1/2 weeks, he was exclusively breastfed. We tried to go "tube to boob" and avoid bottles, although while he was in the hospital we did end up using 2 bottles a day. At home, we're exclusively breastfeeding.
We also used a nipple shiled from 33 to about 40 weeks - this can be very helpful in breastfeeding preemies.
Most preemies go home somewhere between 36-40 weeks gestational age, so hopefully you will not need to stay too long in the hospital.
Another word of advice...if you want to breastfeed twins, you need to try to pump as much as full-term twins would need in the first week. This means 40-48 ounces in 24 hours once you get to 3-5 days after giving birth. This will stimulate things enough that you should hopefully be able to keep up with what they need as they grow.