You need to keep in mind that Imagineers arent strictly engineers. Nor are they just 1 or 2 types of engineers, plus they are usually creative people who can dream up the magic while other engineers are needed to create and better plan it out. They are diverse (done alot of things and have had there fingers in many different pies), and more importantly are usually head hunted (so Disney seeks them out, not the other way around). With an electrical engineering degree, you may not ever become an Imagineer. Rather you might be able to become an Electrical Engineer for Disney.
But either way the best plan would be do get your degree and do the PI when you can. You at least get a chance to be seen/heard of from Disney and your peers.