That sounds like hard work, and those nights sound tiring too, especially with another one to look after.
Her A times look quite short for her age.. How long does she take to fall asleep after you put her down? (A time is eyes open to shut, including time to fall asleep)
Have you looked at the average A times for her age?
Average A times- BOOKMARK ME! I would try keeping her awake a little longer before the first nap (even if it's just 10 mins more) and see how long she sleeps.
I'd then aim to keep her up longer before the next nap- at least an hour-1hr15 before you put her down. If she's cranky before then, would a change of activity or room help?
I wonder whether she's not tired enough to take a long nap at the start of the day, but then gets overtired as the day goes on because the short naps aren't restorative enough for her. The OT might be impacting on her nights too.
Hope that helps
Xxx