When did the Monster Maroons replace the Pyjamas?

[mb22]

Phase II was at least considering using the TOS uniforms (at least in test footage) although pre-production artwork shows some other types.

The TMP ones also resemble the outfits worn in the 1980 TV movie version of Brave New World (shot about the same time), both in their body hugging design and in their whites, greyish blue and earth tone colors

 

[Therin of Andor]

Doesn't that ignore Nicoles attitude towards the mini-skirts?

It was Grace Lee Whitney who fought for the mini. She was very appreciative of the trailblazing work of Mary Quant as a feminist statement (and other people who wore early minis, like Jean Shrimpton).

I found Nichelle Nichols' quote here. She liked the mini, too. But I don't see that the Uhura line in the comic is at odds to Nichelle's view. It's just a retort to Scotty's comment.
https://comparativegeeks.wordpress.com/2016/05/07/star-trek-miniskirts-feminist-or-nah/

The TMP also resemble the outfits worn in the 1980 TV movie version of Brave New World (shot about the same time), both in their body hugging design and in their whites, greyish blue and earth tone colors

Robert Fletcher used the same futures research for TMP as the developers of EPCOT's Communicore attraction at DisneyWorld. Thus they came up with similar designs, fabrics and colour palettes to suit longtime duty in a space environment.

http://www.imagineeringdisney.com/blog/2012/9/13/epcot-30th-a-photo-tour-of-the-past-part-1.html