Hi Michael!
Walt Disney World has an FAQ on
Dressing Recommendations that includes information about dressing up as characters. The basic guideline is you are not allowed to dress as if you are representing a Disney Character. This would mean a full costume is out. Reading the guidelines, it would seem that the Jack wig is acceptable.
Here is a quote from the guidelines:
"Attire that is not appropriate for the parks—and which may result in refusal of admittance—includes but is not limited to:
- Adult costumes or clothing that can be viewed as representative of an actual Disney character
- Masks
- Clothing with objectionable material, including obscene language or graphics
- Excessively torn clothing
- Clothing which, by nature, exposes excessive portions of the skin that may be viewed as inappropriate for a family environment
- Objectionable tattoos
Adults
can visit the parks if their hair (or makeup, if applicable) resembles a
Disney Princess or character, provided that they are not also wearing a
costume or clothed to look like the character."
The only exception to this rule is Mickey's Not So Scary Halloween Party. Children AND adults are encouraged to dress up for that!