I know its a complete confusion! I would try and push nap back to 12.30 - she is only sleeping for 20 minutes anyway so may as well try and get her used to a "permanent" time! I would hedge my bets perhaps and aim for a 5.30pm bedtime, see how it goes.
She sounds like she is chronically overtired - so another temporary option is to switch her back to a couple of naps a day to help her catch up again, then re-start! I have done this with harrison when he has been overtired from night-wakings. Put him down for a catnap early morning for 40 minutes, then gone for a later nap, but I do have to walk him to get him off for the second nap - although this catches up his sleep much quicker. I would only do this for 1 or 2 days though.
The nightwakings should disappear once sleep has been caught up, but it can take some while of the early bedtimes to do this, and depends how many times they wake in this night while it is going on. I find a sleep log is a neccessity, it helps me to see where we are at, and predict the catch up time. When we have been in a particulalry bad spot it has taken over a week of early bedtimes (Harrison will nap until 2.30pm and I get him down by 6.45pm if I can when this is occuring, rocking to lengthen naps, and early morning (5am) wake-ups before we are sorted. The early wake-ups again are a result of being overtired eg if H goes to sleep at 7.40pm and he is overtired he will wake at 5.15am, if I can get him to sleep by about 7.20pm, he will sleep until 5.40am - so it is a question if hitting the magic number - even 20 minutes makes a difference!
When she has woken up an hour earlier - how much sleep has she had overnight?
Keep posting, it is a difficult time to get some of them through, but there is plenty of support here.
Justine