C.
Nap cycle begins with the feed cycle (so hunger is not interfering with nap). I don't know how you are feeding so how realistic it is to feed them at the same time, but I would try a 3 hour schedule with them. If you can't feed at the same time, maybe ones schedule can be slightly later than the others, but anyway, here's what the schedule would look like.
6am eat
7:30-9am nap
9am eat
10:30-noon nap
noon eat
1:30-3 nap
3pm eat
4:30-6pm nap
6pm eat
7:30-9pm nap
9pm eat
10:30pm eat and to bed
Feed on demand in the night, but then wake for that consistent first morning feeding to help them to learn day from night and to train their bodies to sleep consistently and thus sleep together. Keep this 3 hour schedule up until after they are sleeping through the night consistently and then when they show signs of being ready to lengthen the stretches, you can move on to a 4 hour schedule. The naps begin half way through feedings.