Re the dimensions of the scarf - your guess would probably be better than mine, but I'm thinking between 32 and 40 inches long, and 6 to 8 inches wide - possibly a little wider? Some crumple effect is probably desired, but there's only so much that can be hidden under the dress. I seriously wouldn't put this as a high priority, I'm not really sure I can get it to look right.

Re the purse - big enough to hold a few credit cards? I'm thinking that's all one really wants attached to one's belt.