I'm still pondering but your Friday tells us that he does reasonably well with ~2.5 hrs day sleep. His last A was long so I suspect it should be titch shorter for him and he may not have done the EW at ~10 hours in...that's pretty classic OT...I live with one of those 10 hour kids so I know :-) It does look like he does best with a shorter middle A, we can't really look for too many theories here, if it is what he needs then we have to just accept it from him until he changes it up again. I suspect it's due to the shorter night, longer AM A time and then a shorter nap than he is used to. I am beginning to wonder if you need to shorten the middle A even more after a 1 hr nap, maybe he's only good for 2 hr 30...
However, clearly things deteriorated so he got OT either due to his routine being off or teething or because you had to be out of the house or one of the other many million possibilities these kids throw at us. And Sunday after his longer night (even with a NW) he only gave you just over a 1 hr nap on a shorter A time...so looks like he's getting used to the longer A/1 hr AM nap but the rest of the day is going wonky. His first A looks good for him though, so let's keep that. It looks like it's between 3 - 3 hr 20 depending on his night.
I wonder if you could try 2x 1 hr 15 min naps for him? It's different but may work for a kid so sensitive to A times.
What about:
Awake 6
Nap 1 hr 15 @ 9:20 - 10:35
Nap 1 hr 15 @ 1:35 - 2:50
Bedtime asleep by 6:20/6:30 - if he's fighting this I suspect he can actually handle a longer final A after his good naps and his short middle A time, you may even get him to a later BT and still get a good night
Then when he's sleeping better through the night etc. we try adding more A time to get him to where he should be.
It's just one plan and it's no exact science, someone may have better ideas :-) I know you don't want less night sleep/early mornings but it can be out of our hands at times :-) Ideally you want a well-rested kid in the day and night so sometimes we don't get good naps and long nights until they have transitioned and evened out.