Personally I think she has got a bit of an UT/OT thing going on, with the OT caused by the long days, which are in turn caused by the long nap. She's about 25 months now? Lily has always been only slightly LSN (she currently averages around 10.5 - 10.75hrs sleep and the average for a 5 yr old is 11hrs, for example). She was only sleeping 30 - 45 minutes at this age, with some NNDS too. Her BT was earlier though.
She used to take a long time to settle for naps and BT too if she was UT, so by this age I set WU time from her nap at 2pm. I'd put her down at 1 every day and if she was tired she'd fall asleep earlier and get a longer nap. If she wasn't she'd fall asleep later and get a shorter nap. It was a way she could self regulate. Might be something else to try if you are nervous about cutting her nap too much? I think BT for lily was around 7.15 at this age, asleep by 7.30, which gave her around a 13 hour day. By 27 / 28 months her nap had gone so her day obvious shortened again.
I agree btw that teething / development could easily be the cause as much as any of the above! You can only try things out, and if they don't work, then try them again once the teething etc., has finished. One thing to be aware of is that both my LOs had an A time leap when they turned two, so that could be part of it too.