1) Logo–make sure that “Image” is selected in the “Text or Graphic Logo” section (just above where you upload your logo.
2) I don’t have the theme set so you can specify just a background color in the slider/page content area. The background color there is for a fallback behind the image. The blue color scheme has an image so you wouldn’t be able to see the color since it’s behind the image. But you can still use just a color. Paste this code into the box for “Custom CSS” and that should give you the color without the image: