I think where you're getting confused over how to do the comparative discussions, is if you just want a discussion without a poll, or just a poll, or both. You have the same discussion for both the poll and without the poll in this post, but you don't have to do that. After choosing the products you want to compare, simply choose either "add poll" or "add discussion." You can do both if you have more than one thing to ask, but if you just have one thing to ask about, such as the color choice in this particular comparative discussion, you can just choose the poll option, whether you want to allow multiple or single choice, and private or public voting. You can then move on to the next page by clicking the button on the bottom of the screen, and you will then be asked who you would like to participate in this discussion. And that's it! Does that make sense?
As for the lovely vibes you have listed, I'd go with the blue, just because I get tired of pink and purple toys.