While I agree with most of what you said. The John Ehrlichman quote is pretty suspicious.
It was released in 2014, 20 years after the interview. Because allegedly, despite the intense claims and weirdness reported (Ehrlichman suddenly bursting out with this monologue while pushing the interviewer out the door), the interviewer completely forgot about it until rereading his notes 20 years later, while also trying to promote a new book about Nixon. You'd think when interviewing someone that influential, and having them drop a reveal like that would've made it into his book at the time.
But there has never been any corroboration from anyone else about Ehrlichman making these claims, his friends and family say he never said anything like that to them. And somehow, not a single other corroborater to this big conspiracy has come forward.
Ehrlichman was long dead when this claim was released, and thus unable to verify he said it. Most news sources wouldn't even report on it until buzzfeed spread it around, and comedians like 'Adam Ruins Everything' spread it as fact. Not hating on you, just hate disinformation. Nixon did so many fucked up things, yet somehow one bullshit quote by an author desperate for attention gets all the hype.
I think you're a bit mistaken. Per https://www.edf-feph.org/enforcement-toolkit-european-parliament-peti-committee/
"The Petitions Committee does not have investigatory nor enforcement powers and it can only adopt non-binding recommendations. Nevertheless, it can be a good tool to draw political attention to specific matters."
At most, it makes the parliament have to look at the proposal and decide if its worth looking into or not. It doesn't force anything.
Unless I'm looking at the wrong kind of petition to the EU Parliament?