Sabs, I am so sorry. If I were you, I would definately try a later bedtime and maybe even eliminating that CN. I put mine to sleep at 8 pm last night (about 20-25 mins later than usual). I heard her screaming at 9 pm, went in to check on her, and the darn cat ran out.....Grrrr.
But, she slept all the way till 4:45 and then I fed, and she slept until 7:15. Of course, she does this on her own about once or twice a week anyway, but I am sure the later bedtime, plus the larger bottles I give at her DF help.
Trying a later bedtime can't hurt, can it? However, I just don't understand how OT/UT etc can cause as many NW as you are having. It seems much more likely to be some sort of discomfort, but I would expect you would be having at least some problems during the day, right?
I think a later bedtime might help. I am going to push mine to try and make it to 8. I know for a fact DD1 was at an 8:30 bedtime by 5 months.