||1) No. But we try to dress and act as nice as we can on Chol HaMoed in honor of the Holiday. Even more so on Hoshana Rabah (day 7).
But there is clearly no requirement. If you went to Great Adventures in your suit, white shirt, black hat, and tie, you need help. I'm sure you didn't. You're a Goy who wears Jeans. Oy Vey! Everything in moderation with common sense. (which incidentally, is not very common.)
2) If there might be a loss of a special sale, or if there is an urgency, it's OK, but you can't fool God and don't fool yourself. So think it through.