kerry, so sorry for the late reply, i havent been able to get online for a few days.
looking at her routine, i think her A times could be too long, especially since she was 6 weeks early. here is a link to average A times, her times would be between her real age and 6 weeks younger than that. most of the times you had were closer to 2 hrs, try cuttting it back to 1.5hrs and see if that helps. the 1.5hrs includes feeding and also wind down, so start wind down at about 1hr15.
regarding your snacking Q, it actually doesnt look too bad. aim to put her on a 3hr EASY routine so this means feeding 3hrly too (on a typical routine feeds would be 7, 10, 1, 4, 7. if you want to do the cluster feed for now, try it at around 6pm after a catnap, follow with bath, baby massage, pjs, etc and then final feed at around 7pm and settle for bedtime. after you start to get her routine settled you may wish to try a df again, and then drop the cluster feed. will she take a dummy? as you can use that to try and stretch out her feeds to 3hrly. by the way, i could never get my LO to take a bf for df, i had to express and use a bottle and then it worked great. the df would definitely help get her onto one nw for a feed too but keep tackling the daytime routine first. often once daytime is sorted, nighttime settles down too.
also is she swaddled?
HTH