As you seem to recognize, Fair Use does not lend itself to an easy definition. The determination of what is and what is not considered Fair Use is based on all of the facts involved. With animated characters, even when redrawn, there is a high risk of infringing someone's copyright. A derivative work is likely an infringing work. Only the copyright holder has the rights to derivative works. There are certain exceptions, but one needs to consider the entirety of facts to make an appropriate legal determination.
This information should not be considered legal advice for your specific circumstances and are offered only as general information on the topic of your question. This should not be relied upon as legal advice and Sills Cummis and Gross does not represent you until you have signed a retainer letter from us.
Philip Braginsky Sills Cummis and Gross http://www.sillscummis.com/practice/practice_group.asp?id=28
Answered on Oct 12th, 2011 at 1:24 PM