Pretty sure Charlotte wants the technology for something along the lines of uploading human consciousness into host bodies. She was vocally disinterested in the theme park entirely but very interested in the technology.
I think William is just an investor who wanted to keep the park alive. He doesn't want to control what happens. He wants the opposite of that and was hoping 'the maze' would bring him the chaos he thirsted for and give the hosts, most notably Delores, the freedom he initially wanted for her in the past. If you haven't yet, I would recommend re-watching the series. I was ahead of my wife before she decided to watch with me so I had the benefit of watching the first 8 episodes twice- it helps a lot to make sense of all the stray details and clues. I think they really nailed the build and set up...more than for any show I've seen I think. Only Elsie and Stubbs whereabouts were left weirdly unexplained and I have a feeling those are being saved for season 2. Everything else was meticulously set up and explained.