HI- just reading through quickly- sounds like you have some of the same issues I did when my LO was going through the 2-1 switch + teething- fun, isn't it? ugh.
We had a few days with a 45 min nap at about noontime, and we just put him down early to sleep that night- at 6 PM. Then gradually that noontime nap moved longer over about 3 weeks and now we have a 2 hour PM nap from 12:30 or 1 PM on. On the off day that he takes a late nap, we just push bedtime back.
For me, I just realized one day that he needed me to be flexible with his schedule until he was solidly on one nap.
Sounds like you got a little slice of heaven to have the7:30PM-8:45AM night! I don't think I've ever gotten that!
Keep it up, you're doing fine- hang in there, one day it will get better!