I think firstly that there appears to me, as I have observed it, that the sun appears yellow to our eyes, at least it does to mine. It seems quite different if I go to an indoor space with white light. Science surely begins with observation.
Yes, during sunset's the Sun is always more yellow than at midday. If you do a pin-hole projection of an overhead Sun, you will see that it is white. The difference, of course, is due to the change in the amount of atmosphere sunlight must travel to reach us. Blue light scatters as a fourth power law, so very little atmosphere allows much more blue light to reach us, as in the mid-day Sun. This scattering of blue is why the sky is blue.
As you likely know given your photography knowledge, like camera software, our eyes will adjust to make a bright whitish light more white than otherwise. This allows us to color-adjust for various circumstances. If one looks at car head lights (old style lights) in bright daylight, they will have a strong yellow tint. But they will have only a slight yellow tint when seen at night. This is called "color constancy".
In theory it seems logical that light should contain all colours and therefore be white. But, as I have observed in my astrophotography over the last several years, stars have different colours due to their composition.
But all these different colored stars also emit contain all the colors. [This is a common error in logic even made by a surprising number of scientists and journalists who seem to have little interest in getting into the weeds with this topic.]
The light from stars, including our sun, changes with time also as we can see in red dwarfs, white dwarfs etc. So our star the sun will not be pure white.
Yes, ironically, it will someday actually be a yellow star, before it becomes more red, though Earth residents won't be around to see it.
Betelgeuse in Orion is a red colour to the eye and other stars are more white or yellow, or red...check some astrophotography images to see if this is true
Yes. The key to star color is their surface (photosphere) temperatures. Betelgeuse is much cooler than the Sun, which is much cooler than, say, Rigel, which has a blue tint. All O-class stars are very hot and emit more blue light than the color stars, so all three stars of the Orion belt (since we're in Orion at the moment) appear to have a blue tint to me.
But, atmospheric conditions can greatly effect color as well. Pollens, aerosols, dust, etc. all contribute to scattering. The more scattering the more objects shift in color toward red. I once saw a star hotter than the Sun have a strong yellow tint, and this was viewed from McDonald Obs. I was stunned, having made so many posts on how the Sun is only white, with no tint (if viewed from space; heliochromology). But the director of the observatory was with us and he said that sometimes they have to close the domes (protecting the scopes) due to excessive particle counts.
[BTW, thanks for your link! I look forward to someday getting serious with my coming new telescope by having imaging capability. So I need to start learning. I'll have more time later to enjoy your link.]
Also, notice my avatar. This is an accurate color image of the Sun taken off the projection table at the McMath-Pierce solar observatory. Notice that even the cooler (5000K) solar limb isn't yellow, and the center (6390K) has not blue ting. So this is evidence falsifies any yellow Sun hypothesis, but perhaps, in space, it has a slight blue center tint, though I doubt it.