I find writing prompts a useful tool/exercise to help me get through writer's block. I agree sometimes I need to slog through it and just write. Once things start flowing again, then I go back and revise any areas that feel forced.
I think use of an outline depends on the author and their writing process. I don't tend to use outlines, but I do write lots of notes about the story. It helps me remember things I might otherwise forget.
I do the same with most of my characters. They are a conglomeration of people I know IRL. None of my characters are based fully on real people, but a lot of their mannerisms, quirks, and personalities are.
Interesting interview. Thank you for sharing!