Remembering that you're supposed to only ask one question per post... On re-entry, the sky below you is transparent and the sky above you is initially transparent slowly becoming blue as you descend far enough for Rayleigh scattering to matter — if you see any of this at all. Most of the time you'll be looking at the orange of burning stuff as you exchange speed for heat. Note that if you've ever been on a long-distance flight (where the plane gets 6+ miles into the air) you can see what I'm talking about. Directly below you the atmosphere is transparent. As you look out across the world, it appears more and more blue due to increasing atmosphere between you and the terminus of the atmosphere.

Sheesh... during all those times? Remember... one question. Rayleigh scattering needs sufficient sunlight to occur, which is why you don't see the blue immediately before sunset or after sunrise. I wasn't as clear about one point as I should have been, so: atmosphere has no intrinsic color, which is why you don't see any color at night and you wouldn't under your circumstances, either. What color you see at sunrise and sunset has more to do with clouds and the color of your star than the atmosphere, and it has (if I remember correctly) more to do with atmospheric lensing than it does Rayleigh scattering.

#6 is unanswerable. Climate is horrifically complex and changing just one variable like the composition ratios of various gasses probably isn't enough to really change anything. Storms are caused by planetary rotation and orbit, sun energy output, the ebb and flow of pressure in the atmosphere, the presence (and ability to retain) moisture, temperatures all over the place... like I said, it's incredibly complex. As I said, I wouldn't expect your change in ratios to really affect anything at all.

You want links to artists conceptions of your specific gas ratios? Are you asking about a set of ratios so well known that anyone would render the condition in art? (Keeping in mind that the above photo is really all you need.)

I'll be honest with you — hard sci-fi authors are almost always people who have earned their college degrees and use those degrees and a lot of industry experience to provide the technical detail that makes the stories hard. If you want to write stories to that detail, you need to get that education. You can't make up for it by getting quick answers from a site like this. In my opinion, you're striving for far, far more details than you really need and a sense of "reality" that's irrelevant since few in your audience will know if you're right or wrong — and for a couple of those questions (like #6), nobody will know if you're right or wrong. Remember that we have just one data point to work with when it comes to habitable planets: Earth. Everything else is nothing better than a best guess.

EDIT: This answer was posted before the present edit to the question. I encourage everyone to answer the current edit.

On re-entry, the sky below you is transparent and the sky above you is initially transparent slowly becoming blue as you descend far enough for Rayleigh scattering to matter — if you see any of this at all. Most of the time you'll be looking at the orange of burning stuff as you exchange speed for heat. Note that if you've ever been on a long-distance flight (where the plane gets 6+ miles into the air) you can see what I'm talking about. Directly below you the atmosphere is transparent. As you look out across the world, it appears more and more blue due to increasing atmosphere between you and the terminus of the atmosphere.

Rayleigh scattering needs sufficient sunlight to occur, which is why you don't see the blue immediately before sunset or after sunrise. I wasn't as clear about one point as I should have been, so: atmosphere has no intrinsic color, which is why you don't see any color at night and you wouldn't under your circumstances, either. What color you see at sunrise and sunset has more to do with clouds and the color of your star than the atmosphere, and it has (if I remember correctly) more to do with atmospheric lensing than it does Rayleigh scattering.

#6 [referring to an original question about climate] is unanswerable. Climate is horrifically complex and changing just one variable like the composition ratios of various gasses probably isn't enough to really change anything. Storms are caused by planetary rotation and orbit, sun energy output, the ebb and flow of pressure in the atmosphere, the presence (and ability to retain) moisture, temperatures all over the place... like I said, it's incredibly complex. As I said, I wouldn't expect your change in ratios to really affect anything at all.

Finally, it's unlikely there are any artists conceptions of the sky from either the surface or space at that time. If there happened to be one, I'd question it's presentation of reality. For as much as we know about the Archaean time period... we really don't know that much about it.

Sheesh... during all those times? Remember... one question. Rayleigh scattering needs sufficient sunlight to occur, which is why you don't see the blue immediately before sunset or after sunrise. I wasn't this clear, so I need to make a point: atmosphere has no intrinsic color, which is why you don't see any color at night and you wouldn't under your circumstances, either. What color you see at sunrise and sunset has more to do with clouds and the color of your star than the atmosphere, and it has (if I remember correctly) more to do with atmospheric lensing than it does Rayleigh scattering.

Sheesh... during all those times? Remember... one question. Rayleigh scattering needs sufficient sunlight to occur, which is why you don't see the blue immediately before sunset or after sunrise. I wasn't as clear about one point as I should have been, so: atmosphere has no intrinsic color, which is why you don't see any color at night and you wouldn't under your circumstances, either. What color you see at sunrise and sunset has more to do with clouds and the color of your star than the atmosphere, and it has (if I remember correctly) more to do with atmospheric lensing than it does Rayleigh scattering.