Yeah. I am not sure how close you can get. I mean, we do not want to work HC staff overtime. They do this voluntarily and they have better things to do.
At Disney Land/World you (past age 14?) cannot dress as a Disney character. This is not due to trademark practices, but because it can confuse young guests. So die hard fans that are pros do something called "Disney Bounding" where they dress with similar colors, maybe a ribbon in the hair to match, but do not "copy" a character obviously enough to fool anyone.
An homage character, with "hints" at the influence, and a DIFFERENT name, might be fine. Or pick something that is in public domain, like, maybe a nosferatu lol.