Hi Melissa,
My 2-year-old son also loves "Quest for the Crystal Mickey" and following along with his pal, Kansas City Mickey. In fact, just reading your question made me start singing, "Kansas City Mickey, Kansas City Mickey..." and I am sure I will continue singing it for the rest of the day.
Although I haven't seen any plush Mickeys directly from the movie, I have spotted Indiana Jones Mickeys at the Indiana Jones Adventure Outpost in Disney's Hollywood Studios, and the resemblance is very similar. Merchandise in the parks is always changing, so of course it is subject to availability, but you can also find them online through various sites.
For fun before your vacation, my son loves the
Quest for the Crystal Mickey coloring pages you can print from the Disney Junior website.
Have a wonderful vacation and enjoy your magical adventure! I am sure like Kansas City Mickey, it will "Go down in his-to-ry!"
See ya Pal,
Lauren