Hi, I'm no expert, look at my own EASY posts! But, thought I would try to help while you wait for the smarter people to pop in!
Thinking to what our EASY was at 4 months and what A time my DS can handle now at 6 months, I have a few thoughts.
First nap, you started winddown at 8am, I would say this was too late. Although, every baby is different and this will depend on your LOs temperment (have you done the quiz yet to see if you have an angel, textbook, grumpy, touchy or spirited baby?) The first A time is often shorter than what your LO can normally handle. Ie/ I think of my DS as being 2 to 2h15min of A time, but for his first A time it is 1hr45 min. It seems that your LO is overtired, and you may want to think about starting your wind down at 745 and aim to have her asleep closer to 800ish. Then, when she woke at 920 if you aren't able to extend, this is the hard part - has she usually eaten on a 4 horu schedule or are you just moving to it? When we were just moving to it, I did the same, but once it was well established, I would have put my LO back to bed after that yawn and aimed for another 30+ minute nap. It's hard when you are just moving to the 4 hour though!
I would say that for the second nap she was OT as well, because she was up from 920 to 1115 on only a 45 minute nap. And your day probably went from there. I really did find that with us, the key was getting that first nap bang-on that helped.
I also learned with my DS that while he can laugh and giggle his little pants off at 630 am, I can't let him. Any other time of the day it doesn't affect him as much, but that first morning A time needs to be spent nice and chilled out, no laughs, no practicing his new skills, etc or it ends up with him tired but tired from overstimulation instead of from being awake, and the day is all off.
Hope someone else comes along soon with some better advice than mine, maybe mine will help a bit!