She might not be its just with stuggling to get through that first sleep cycle at 30 mins is an indicator thats she is OT. But this can also happen if she is feeling under the weather or teething. So it could be that aswell. What happened when you capped that AM nap at 1hr instead of 45 min? It could be due to the long A followed by short nap that causing OT for the second nap but i still think that you should push through it and keep that PM nap at 3hr15 after the 45 min nap as i think she does need more A for that pm nap and eventually she will get the hang of it & be able to deal with it ok if that makes sense.
I think that pm nap needs to be no earlier than 1.30pm so that you can get a good bedtime, if she does 1.5 hrs at 1.30-3 then bedtime can be at 6.30. Obviously if she goes 1.30pm- 3.15 bed can be 6.45, etc. i wonder if you capped AM at 1hr instead of 45 min, but then gave an extra 15 min for the PM nap A time (hoping she can handle an extra 15 min A because of a slightly longer nap in the AM) then that could spread the naps and A out better. Eg, wu 5.45, nap 1 9.30-10.30, nap 2 at 1.45/2-3.30, then you can get bedtime to 7pm. The extra A time in the aft & later BT may help with the EWU. Would that work, i cant remember what you said about 1hr AM nap xx