Hi. I've just read through your thread.
I'm wondering what his routine was like before the 1-0 started? I mean before you capped naps and nights went short - the last time you were on a steady routine where he was fully rested. Can you remember?
So, my experience with the 1-0 was that DS was clearly in the transition but could NOT cope with a capped nap and neither could he cope with a NND (we have a scar on the forehead from an attempted NND where he was standing still and just keeled over at 4.30pm, needless to say I didn't try that again!) so like you we had a few months of messiness. Here's what I found though...
Good routine: Nap was set at 2hrs 2-4pm, BT 8pm.
When nights went as short as 9hrs or even less (total sleep 11hrs in 24) I felt I really had to do something.
Attempts at capping the nap - huge fail - DS was a mess, nap was shorter, nights were still short, overall less sleep and a very grumpy boy.
Attempts at one NND per week - huge fail, by 4.30pm he was a mess and a danger to himself.
More attempts at capping at 1.5hrs - not great.
In time I eventually realised that we were back on our original routine. 2hr nap and roughly 10hr night. I was supposed to be capping at 1.5hrs but couldn't bare the melt downs so was often leaving him the full 2hrs and do you know what, I think he had 'tried' the transition thing and decided he wasn't ready. May sound a little crazy.
Then one day he was poorly with hand, foot and mouth. He slept a 2.5hr nap (I didn't wake him as he was poorly). The following day he refused his nap and pretty much that was the end of napping.
I did try the odd car nap but discovered this made him very angry. If he nodded off in the car it was best to let him but to wake him on arrival somewhere, not to leave him to sleep longer. Micro naps really.
After around 2wks of not napping and getting more cranky (I was exhausted!) I invited him to nap in bed with me, he had never slept with me before and I didn't think he would go for this but he agreed, we both slept on and off for 2hrs. And that really was the last of the real naps. This was at 2yrs 7 months. Since then he only falls to sleep if in the car for a micro-nap once in a while.
I felt very strongly that my DS needed a regular routine every day the same. If that meant long nap and short night then that was it, when he dropped the nap (cold turkey in the end) his routine was again regular, same every day, predictable and this is what he needed. He couldn't cope with capping or some days napping some not, too unpredictable, it never gave his body a chance to adapt. When he stopped napping I think I was happy to get 11 to 11.5hr night. Over a little time this increased to 12hrs - btw he NEVER did 12 hrs as routine, only ever for a short period through a nap drop or illness so the new 12hr nights were unbelievable to me - a real treat!
Looking at what you've tried I think I would be tempted now to just let him sleep a long nap. Even if it makes nights short, it may be the balance he needs to get the most sleep he can and at the time of day he needs it.
If (especially after some long naps) he refuses a nap then I'd let him lead on that, do EBT and continue to offer the nap the next day. So:
WU 6am
nap 2-4
BT 7 (if it takes an hour to go to sleep) for S 8pm
or
BT 8pm if he will go to sleep quickly.
or
I would even go later with BT if you get refusals because he does have the option to sleep later in the morning and did do it one day which proves he can in the right circumstances.
You never know, he could do what mine did - one monster nap and then a cold turkey drop!
If you decide to continue with the capped naps I would bring BT much earlier, I don't see how he can cope with a 20-30 min nap and less than 10hrs at night. So:
WU 6am
nap 2 - 2.20
BT 5.30/6pm for S by 6.30/7pm
Another thing I wanted to mention is he is 2.5 yo so he is going through the half year developmental phase which can really throw things off - yk just in case you weren't thrown off already. He might actually need more sleep just now but have more disturbed sleep too, NWs may be OT/UT of they may be just a part of the usual half birthday messiness which you have wrapped up along with the 1-0 messiness. Basically I wouldn't read too much into NWs around this time.
I hope this doesn't just add to your confusion! 1-0 really is a messy time. You're clearly putting a ton of work into it, and maybe this is a time to listen to him rather than us?? if he is shouting at you to let him sleep, well, maybe let him?
Happy to answer any questions you might have about my experience if you have any.
((hugs)) too - you'll get through this.