From a marketing standpoint I think the strength of the book will be the comprehensive recitation of TIGHAR's evidence in Part II. It's something that has been needed for a long time.
Recommend that you make it clear that the evidence that your are presenting is pursuant to the rules of evidence and is consistent with the scientific approach that you have stated that is being used to test the hypothesis. The evidence should be chronology listed as evidentiary exhibits along with the commentary that explains the relevance. The burden of proof is on you to convince the court of public opinion. To do so, your argument will have to ascend from the level of preponderance of evidence to the level of clear and convincing. Arguments are legally presented in the form of a legal brief with a memorandum of law is support. Of course, this is probably not what you would want to do as legal citations are meaningless to the layman.
If you have access to a law library, I would suggest research on the rules of evidence and the law that construes those rules. The Hornbook series is very good as is the Corpus Juris Secundum. Your evidentiary argument must be presented with precision as I am sure there will be many who will be ready to shoot holes in your case. There are those who think that you are a fraud and that your project is nothing but a pretext to solicit money for profit.
I am not quite sure that your evidence thus far is sufficient to make a clear and convincing argument, however, it can be argued that the body of circumstantial evidence supports the inference that Earhart landed on Gardner Island sometime in the morning of July 2, 1937.