1) If any warning persists even with the default theme it means that our theme is not the reason of the problem. Anyway, I logged in to help you with the second question and don’t see any warning anymore. Have you sorted out?
2) As I have told you to change the color of the headings go to Theme Options > Typography > Content > Headings > change font color, watch the video if you don’t understand what I’m talking about https://gyazo.com/3a1686047603fde060cf4bfe9f8e5a3f
