I'm Brown skin would this be great for my skin tone

I think you should try la girl spice

Is the bronzer/contour a matte color?

Yes, the bronzer is matte, it's a very nice set for the price. It's not as nice as Too Faced cosmetics but it doesn't cost $30.00 either. I am enjoying this purchase, I am going to order some of LA Girl eye shadow bricks next.

What are the names of the shades in order from left to right?

There are no names on it, I believe these colors do not exist individually in their line although you might be able to find similar colors specially in their blushes.

What’s the true difference between the sets Glow and Spice? Which one would be more subtle for light skin with peach undertones?

I don't own the spice, however, the Glow does have a bright peachy coral color to the blushes. When applied, the colors are smooth and light. It does not take a lot of application to see. The bronzer is a smooth bark color and the highlighter is a nice cream. (Note: I have an ivory complexion with rosy cheeks.)