I see you've already have lots of great help and support
I really just wanted to add...
I know the EASY schedule I'm aiming for and until last day or two I've been trying really hard to make sure his routine revolved around 1hr15 of E&A, 15minutes of wind down and shush pat
This looks like 1hr 30 A time which you are aiming for which is about right for the guidance times for age but the thing is, these are only *guidance* times and each LO is different. My own DS needed much longer than the guidance A times and we do see LOs who need significantly longer (or shorter) than the guidance times. I kept my DS on too short an A time throughout the "regression" as I had no experience of these things.
If you see debs link the A times are 2hrs which is the higher end of guidance fora 4month old but some LOs need this earlier.
A times increase pretty quickly over this period and to be honest I think most of us don't expect it - it caught me out I know that.
I would increase the A time again and use W2S to help LO stay asleep - use a firm hand or shush/pat throughout the entire nap if necessary. There's no need to try to introduce a paci at this point (imo) if LO has taken one to this point but equally don't be scared of giving the level of help needed through this difficult time.
WRT the 5.30am WUs I would say ther are two options:
1. treat as a night wake stay in the room and continue to try to re-settle until 7am - then get LO up whether or not he fell asleep and do a FULL A time. This will lead to OT but my understanding of the BW books and Tr5acys methods were to get LOs into routine as quickly as possible which initially meant a level of "setting" times for a short period and to keep LO up until the correct nap time by any means possible, doing a fan dance if necessary.
2. just accept the 5.30 start for now and get up. Start timing A time from here and begin first nap after a full A time. Once the routine is better settled you can gradually move the entire day on, it's a longer term plan.
hope this helps - I'm not around quite as much at the moment as I have a health issue - but it seems you are in good hands here anyway. Just adding my additional thoughts and sending a hug your way.
You will get through it.