Looks like you are having a lot of fun with your themed releases. :)
I am! I've always liked themed releases. Last year I dedicated my bookcrossing activity to Canadian stories in honour of the sesquicentennial of our Confederation, and I ended up doing way more releases in 2017 than I've managed in other years. Since we were also trying to see/do/experience a lot of Canadian stuff, I was able to do a lot of themed releases... and now it's hard to go back to normal ones, lol. It may not always be practical for me to theme my releases, but if I can manage it, that's my preference!