You may compete as an Amateur only if you have not been paid for a body painting.
As I do not see any body paintings in your MM portfolio and as your are new to body painting try to take some workshops. If you do compete the days are long and it takes a lot out of you. Workshops will add to that, if not there do take some classes in the USA. People ask as lot of advice on line, look at a lot of others portfolios to learn but getting with a pro really can advance you more quickly.
As for your kit pack light esp since your traveling around. Supplies and product is available for sale at the WBPF.
I sugget you take and extra 1-2 memory cards and extra battery for your camera. It is easy to fill up your camera fast as there is just so much eye candy.
Have fun the change to July 4th dates will keep me from returning to Austria for at least another 2 years. I make so much money over those dates I can not justify the financial loss. This is true of several good American body painters who also run face art businesses, we just can't make those new dates.