Sour taste could be tannins from steeping at too high a temperature; though I wouldn't describe typical tannin flavor as sour but I can see how it may taste that way. 170 (assuming it didnt go over at all) should be okay but you usually want to stick mid 150s. Steep time shouldn't be an issue. As far as color goes, with a recipe kit, that is how it is designed so not much variation there. If you look at English browns, e.g. Newcastle, they're typical more pale in color than the American brown ale. I've seen some american craft browns that are quite dark so it may just be what you're looking to make. But my guess on the flavor is tannin extraction... And there is always the sanitation threat and the beer may still be "green". So let it sit a couple weeks, flavors mellow out and malt comes through; may be a completely different beer then. But good job on the note taking. It will definitely help you in the long run. Consistency is key.