Hello, sorry for delay
3.3v regulator survived (suppriaingly)
With wifi module desoldered nothing was getting hot.
uC replaced, programming using fallback procedure #3 bossa went flawlessly.
I disabled wifi section in coning file (not sure if this was necessary) and board works with uart only.
Warting for new wifi module. I will take opportunity to upgrade to esp-07s.
I will post updates.

@knutselsmurf there is no easy fix, because you need two separate UARTs to drive the PanelDue and the Neopixel board, and the only user-accessible UART on Duet WiFi is the one connected to the PanelDue port.

@curt-darius unless a custom plugin is produced, correct.
You may want to look into whether BtnCmd can provide that https://github.com/MintyTrebor/BtnCmd/releases

Figured it out. Needed to add M575 to config.g. All good now:

M575 P1 S1 B57600

@dc42
I know. I can't get AU anywhere:(

Your video is private and I cannot access it.

Can you go through these troubleshooting steps and see how far you can get?

https://duet3d.dozuki.com/Wiki/What_to_do_if_your_Duet_won't_respond

@JDigglyWiggly I did it out of sympathy for a dad with 3 kids under 10.