I love those shoes and to me they seem like they would be pretty versatile.
To answer your general question, I struggle with the same. It's a look I gravitate to because I think it suits me very well but I constantly battle with whether I'm going too costume-ish.
When I had the custom dresses made over the summer I was careful to not pick the red polka dots for instance because I was afraid the combo of the style and the dots would be too much into that territory. I do have a red polka dotted top though with the same vibe that I feel is easier to mix up.
Sometimes I just go for it though, because at the end of the day, costume or not, I really like the style and I think it looks great on me.