Without console and/or the reset button, you're out of luck. All recovery routes require some form of this. Even to get the device to boot from USB to recover requires a press of the reset button at turn on.
I'd try the USB boot with turning the device on and pressign the reset button just in case the reset block is set and takes effect after boot.
USB Automatic Recovery documentation can be found here
https://kb.juniper.net/InfoCenter/index?page=content&id=KB23882&actp=METADATA
KR
Adam