I think the guy says "that man can get anything he wants" when referring to the MiB. I also think that the story with William is the beginning of his obsession with the park and he transforms into the MiB. At first he cares about the hosts. Then over time he doesn't give a shit about them because, well, his focus changes. You can see that he has been pretty horrible to Delores over the years with that possible rape scene or whatever. You also mention his dealings with Lawrence over and over. I mentioned it before that the Lawrence with William seems like the Lawrence who is used to his loop. While the Lawrence with the MiB seems used to being taken out of his loop through adventures with the MiB because he seems more "mature." There's also the screens that show William entering west world while it had the old school logo while in the present scenes it very clearly uses the modern logo. Etc.
Also you mention "in the park" storylines. There's the multiple scenes with Bernard interviewing Delores in that secret little room under the house that now is where Anthony Hopkins is making the people he kills. I'm also assuming that Bernard was his partner at one point and was made into Bernard. I'm blanking on the name right now.
One thing I'm wondering is why are there schematics and plans for only Bernard and Delores down there that Bernard looks at.