So, I'll pop up to the first post first, then get into more of the questions in a bit.
The first hoop looks like it's just simply looped. I would imagine it is somewhat felted, otherwise it would just fall apart with little effort. (Someone comes along and pets it a little roughly... A kid or cat bats at it...) The second definitely looks like a thick and thin hand spun yarn. It can be a bit tricky to achieve that regularity at first, but with practice it's not so difficult...
The first one looks as though it was made of WOOL TOP. Roving and wool top are similar, but only because they come in long rope like structures. That's the only thing they have in common. You'd want the wool top, with the fibres all running parallel for that same look. The roving isn't nearly as smooth, since the fibre run every which way.
For blending colors, you can do that successfully on a set of combs, but the trick is here, that when you do this, the fibre is a lot lighter and less compact than you get from commercial top. Which then would be even more prone to just simply disintegrating if you looked at it the wrong way. Your best bet for adding color is to either dye it, or buy it in many colors, strip it into thin bits lengthwise and layer them as you like.
As for the dyeing, even koolaid or wiltons gel food colouring works well. You get unpredictable results, but they are safe for any pot, and a good place to start. As soon as you get into the acid dyes (Best for protein fibres) you have to have special pots, and a lot more safety equipment. (gloves, masks, aprons, etc..)
Hopefully some of that is helpful
Yes! That was all super helpful! I've purchased some roving, because I wasn't too sure exactly what was used in that top photo. But I didn't get too much of it. Maybe I'll mess around with it while I get started. And I'll get the wool top as that gets used up. I might have to resort to already dyed top until I get more familiar with the material. Then I can start trying to dye some of my own.
The bottom photo, did the artist just take the wool & spin it tighter in some places? Is that why it looks the way it does? That seems like a lot of learning to do! Not to say that I couldn't learn, but I think I might me a long ways from that. But it's a goal to set for myself in the future!
By the way, thank you so much for your help! I really do appreciate it. And I'm glad I didn't spend too much money on the incorrect material to use. That was a close one!