Carpet obviously makes a difference, as far as I know always measurable, and usually quite easily audible. The effect is not subtle in most cases, so as far as I'm aware there is zero controversy about that.
As for paint, I would imagine that paint itself might possibly make a difference that is measurable, but unless you're painting over a surface like metal or glass that is highly reflective, I would very much doubt that the difference would be within the realm of audibility. (For that matter, I would not entirely rule out the possibility that a highly textured matte paint vs a super-glossy, ultra-smooth-finish paint might produce a very small measurable difference, but again I would hypothesize that difference would be too small to be audible.)
As for paint color, of course not - however, there have been many, many studies over decades showing that humans do have different perceptual responses to different colors. I'm not familiar enough with the scientific literature to know how consistent those different responses are across gender, culture, and so on. But it certainly is possible - and I would say possible bordering on likely - that certain paint colors in a room could produce an objectively measurable change in people's subjective perceptions of sound.
Again, the question of repeatability is an open one there, and so as a practical matter paint color might not be a factor one can predict and therefore might be functionally irrelevant since its effects could never be predicted reliably. And of course I don't buy the idea that paint color objectively changes the sound.
But I am pretty sure that color does have measurable effects on subjective human sound perception.
