1. About the background: That is not a bug
The colors are coded like this in the CSS of the extension. If you want the extension to blend in with your custom style, you would need to write an according CSS for that I guess... I don't really know much about styles, so maybe also ask in the style support forum.
2. About the rights: It has to be something with f_survey_answer. The third screenshot is actually not the one that shows the "real thing". When you are in ACP, go to permissions, then on effective permissions
(all the way down on the left hand side). There, look up what the effective permission for the user/group in question is.
@netzversteher: Look at the third screenshot from pvu, it shows how to assign the rights. They can be found under permissions -> Forum permissions -> Content.