ESP8266 using special digital pins (D0,D3,D4, and D8)

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I am working on a project with NodeMCU ESP8266 12-E, and am finding I need to use some of the digital pins that are "special". In particular, Pins D0,D3,D4, and D8.

Now I have read two articles esp8266-pinout-reference and esp8266-pinout-reference-gpios that explain what the best ones to use are and that for the above, to use with caution.

I honestly just may not be comprehending what is very clear to others, but would someone be able to help clarify the comment of "HIGH at boot"? My use case would be to use say D0 one to toggle an LED. Is this just saying that upon reseting the ESP8266, the value output from D0 is high and later my setup function is perfectly OK to write it back to LOW? Basically is this just a warning that if I was using this to trigger something else like start a motor it could briefly turn on until I manage the Pin in my setup/loop functions?

The other concerning comment in the articles is "boot fails if pulled XXX". Does this mean writing or using internal pullup/down resistors? Does this mean do not use them EVER, or simply there needs to be some waiting period post boot before I can initialize a pin as pullup/down?

Thanks in advance!

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Hi,
in this link the author explains very well the behavior of each ESP8266 GPIO.
https://rabbithole.wwwdotorg.org/2017/03/28/esp8266-gpio.html

Table of boot mode dependent on GPIOS level

GPIO
15  0   2     Mode Description
L   L   H      UART Download code from UART
L   H   H      Flash Boot from SPI Flash
H   x   x      SDIO Boot from SD-card

The normal boot of the ESP8266 12e is via SPI.
D0, GPIO16 Can be used for any function without restriction.
D3, GPIO 0 During boot it should be HIGH, after boot finish can be used without restrictions.
D4, GPIO 2 During boot it should be HIGH, after boot finish can be used without restrictions.
D8, GPIO15 During boot it should be in LOW, after boot finish can be used without restrictions.

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