TECHNICALLY all you need is a knowledge of programming and an electronics background. (basically it is a robot set to music) but since the ts failed to include a budget, or what skills they have my advice is very limited.
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Well that depends. We've built several but no "humans". Most of what we did was almost 20 years ago for Halloween displays at home. It did take a fair amount of computer hardware and software knowlege. Our first system wasn't able to edit a show so you had to record all the movements at once. Make a mistake, do it all over. That didn't last long. Our second used a much bigger (not by today's standards) computer (PDP11/23) and would allow you to punch in edits while the show was playing. Much better!
Today you can buy controllers off the shelf to do much of it. If you're not into writing code or building hardware and it's a simple character you can even use midi (musical instrument digital interface) hardware for your controller. There are a number of programs, some pretty inxpensive, that can record / play both midi and digital audio. There are a few companies that make midi to relay driver boards that you can use to control pneumatic valves and actuators. Record your sound track digitally and then perform the characters animation on a midi keyboard. Depending on the software you can even go back and correct animation mistakes. This is a pretty simple system with no positional feedback from the character so the positions are not very accurate. Think Chuck E Cheese characters. We did a controller for Mr. Munch (the purple furball) that performed the Monster Mash.
We had lot of fun doing our systems but in our area, Halloweeen isn't a big thing any more so we quit setting the stuff up about 10 years ago. I just gave away my last controller a couple of months ago.
Making something do something over and over is easy, you can just have a motor spin a cam or something. But when it comes to actually controlling the distance and speeds that are somewhat random, then it gets tricky.