It is often missed that the hardware features required to make this work on Esp8266 have restrictions on the pins that can be used.

The DMA method (the default on Esp8266) ignores the passed in PIN and only works on RDX0/GPIO3. Some hardware boards have built in level shifters on this pin that are "IN", which will stop this pin from being used for "OUT". The Adafruit HUZZAH ESP8266 is one such example.

The UART method (NeoEsp8266Uart800KbpsMethod, NeoEsp8266AsyncUart800KbpsMethod, or other variants) also ignores the passed in PIN and only works on TXD1/GPIO2.

Due to restrictions on the hardware used for these two methods there is no way to support other pins.