Lord Peter Hill-Norton in-chief of the Defense Staff, First Sea Lord, HMS Ark Royal, HMS Decoy
Master Sgt. Dan Morris - US Air Force
Don Phillips USAF and CIA Contractor
Sgt. Clifford Stone - US Army
Paul H Utz - his dad worked at area 51 and became a whistleblower.
Captain Bill Uhouse - Marines
Lieutenant Colonel John Williams
Gary McKinnon - one of the most famous hackers of our time
Donna Hare - NASA Contractor
Astronaut Edgar Mitchell from Apollo 14
Dr. J Allen Hynek - astronomer, professor
Astronaut Gordon Cooper - aerospace engineer, Air Force pilot, astronaut from Project Mercury.
Let's just start with these. I can give you way more names. I want to know why you think they're not credible or how you can invalidate what they've said?
Again, the thing that gets me the most with UFOs and aliens are the countless credible witnesses. I don't know if there's anti gravity or free energy. I do know a lot of credible people say there is. It makes me lol when people say they're "not credible" as if they have a more credible background.
https://www.disclosureproject.org/access/es-wit-test-government.htm
OK, I've spent about 75 minutes on this which is frankly longer than it deserves. In that time I couldn't get through all the names on your list, so I just started at the top and worked my way down. Here's what I found:
Peter Hill-Norton - UFO believer, no claims at all that I could find about antigravity or free energy
Dan Morris - The only quotes from him I could find had their origins with Steven Greer and the Disclosure Project. Heck, I couldn't even verify he was an actual person. But the quotes did reference free energy, so there is that I suppose. I found this bio on him at the disclosure project, "Dan Morris is a retired Air Force career Master Sergeant who was involved in the extraterrestrial projects for many years. After leaving the Air Force, he was recruited into the super-secret National Reconnaissance Organization, or NRO, during which time he worked specifically on extraterrestrial-connected operations. He had a cosmic top-secret clearance (38 levels above top secret) which, he states, no U.S. president, to his knowledge, has ever held." Yeah, 38 levels above top secret, with a higher clearance than U.S. presidents. Yeah, that sounds like a thing.
Don Phillips - I found this speech by him, . He talks about UFOs, so obviously a believer. That video doesn't make any claims about the US having antigravity or free energy technology though. I did find some other quotes attributed to him that reference antigravity, but as with Dan Morris the only sources for these quotes seem to be Steven Greer himself.
Clifford Stone - I found this video of him, . It's an hour long. I watched about 8 minutes, and it only took me that long to find him completely unreliable. He's telling second and third hand accounts, and using phrases like "I have reason to believe" without giving any evidence. My assessment: he is nuts. Definitely not credible.
OK, that's enough of that. All of the people on your list clearly come from this source: https://www.disclosureproject.org/access/es-wit-test-government.htm
And let me be frank: I think Steven Greer is a con man. I do not trust anything at all from that source. I think he has combined statements which are either made by crazy people or are outright fabrications, along with some few quotes from more credible people which aren't nearly as outrageous.
Because I was particularly interested in so-called antigravity technology (since I'm a physicist), I looked at one of the people at random that the page claimed talked about antigravity stuff, namely Bill Uhouse. The quote/bio from the page is: "Bill Uhouse served 10 years in the Marine Corps as a fighter pilot, and four years with the Air Force at Wright-Patterson AFB as a civilian doing flight-testing of exotic experimental aircraft. Later, for the next 30 years, he worked for defense contractors as an engineer of antigravity propulsion systems." OK, so I looked up Uhouse and found this video by him, . I encourage you to watch the video and see if you find that individual to be credible. I do not at all. He's either making crap up or else he's just gone loony. Personally I'm going with fraud. The video actually starts off somewhat OK, with him talking about some things which could be plausible (tunnels for nuclear testing, etc.), but then rapidly goes off the rails. By about 5-7 mins in (I stopped at 7 mins, fwiw, couldn't take it anymore), he is talking about aliens existing at various facilities around the country, that he has met with them personally after going through a "long period of education", and he starts describing various types of alien races and cultures and their interactions. Sorry, I don't find him credible. And of course there is no evidence. Although actually, there could be if it were real... among other things, somewhere in the video he claimed that alien technology was used in the F-117 aircraft (stealth attack aircraft, introduced 1983, retired 2008), with the implication being its propulsion system because it was right after he was talking about flying discs. So gee, there's something that someone could check. I'm sure there were thousands of people, maybe even tens of thousands of people who worked on designing and operating that aircraft line during those years. Too bad none of them ever thought to mention that its propulsion was crazy, like nothing they had ever seen before and completely unrelated to any other propulsion systems that US aircraft had previously used. So again, I don't believe him and have concluded that he was either a fraud or crazy.
Please consider that if you are correct about this, it would require a cover-up FAR exceeding the scope of what some people believe was a cover-up about the Apollo moon landing (and even the scope of that supposed cover-up is way too large to be credible).