Waking in the early part of the evening is generally caused by OT. And looks like there are two tweaks that might help

The CN usually falls later in the day - for us it was always around 5, so I would try pushing that later, maybe put it at 4.30? And let her have 40 mins but not much more. A time to bed is probably a bit too long for her right now.
Is she waking up particularly on those days when she's have a short nap for her second nap (you say it's sometimes 45 mins, sometimes 1.5 hrs)? I'd keep an eye on what's happening with that nap because the 45 mins nap probably indicates that she could do with a bit more A time, looks like some days she needs some more A to get a longer nap there, and some days it is just right, when she does a 1.5 hr nap. So have a look at what's happening there and see if you can encourage her towards more consistency in longer naps. If you're adding on some A time, just add 10 mins and stick with the new time for a few days. And pushing the CN later in the day may encourage better sleep at that time too.
If you're doing a DF, then I would try to stick with that whatever else is happening. Perfectly normal to have a DF and a NF at this age.
