You were seemingly implying - I can't read your mind - that the Kennedys were interested in killing numerous foreign leaders. As in multiple figures. In fact, the evidence I've seen is that they were "interested" in just one: Castro. And more than just "interested". I think they were quite aware of the plots and implicitly if not explicitly approved of them.
As to Diem and Trujillo: Again, where's the evidence? Didn't Lodge offer Diem and his brother protection in the US Embassy? And they rejected it? I don't think there's any evidence that JFK approved of or signed of on their murder. Same with Trujillo. No US government involvement.
"The United States did not want Diệm and Nhu to form a government in exile and
wanted them far away from Vietnam. Assistant Secretary of State Roger Hilsman
had written in August that "under no circumstances should the Nhus be permitted
to remain in Southeast Asia in close proximity to Vietnam because of the plots
they will mount to try to regain power. If the generals decide to exile Diệm, he
should also be sent outside Southeast Asia." He further went on to anticipate
what he termed a "G?tterd?mmerung in the palace".
We should encourage the coup group to fight the battle to the end and destroy
the palace if necessary to gain victory. Unconditional surrender should be the
terms for the Ng? family since it will otherwise seek to outmaneuver both the
coups forces and the US.
If the family is taken alive, the Nhus should be
banished to France or any other country willing to receive them. Diệm should
be treated as the generals wish.
After surrendering, Diệm called Lodge by telephone for the last time. Lodge did not
report the conversation to Washington, so it was widely assumed that the pair last
spoke on the previous afternoon when the coup was just starting. However, after
Lodge died in 1985, his aide, Colonel Mike Dunn said that Lodge and Diệm spoke for
the last time around 07:00 on 2 November moments after Diệm surrendered. When
Diệm called, Lodge "put [him] on hold" and then walked away. Upon his return, the
ambassador offered Diệm and Nhu asylum, but would not arrange for transportation
to the Philippines until the next day. This contradicted his earlier offer of asylum the
previous day when he implored Diệm to not resist the coup. Dunn offered to personally
go to the brothers' hideout to escort him
so that the generals could not kill him, but
Lodge refused, saying, "We just can't get that involved." Dunn said, "I was really
astonished that we didn't do more for them." Having refused to help the brothers to
leave the country safely, Lodge later said after they had been shot, "What would we
have done with them if they had lived? Every Colonel Blimp in the world would have
made use of them."
-- Wikipedia
The Church Committee found that US officials wanted Trujillo overthrown and that some US officials knew of dissidents' requests for sniper rifles and other weapons, and that a handful of weapons were eventually given them. (
Link )
As to the Wikipedia quote: there's no source for the claim that Mongoose also involved the assassination plots against Castro. Again, my understanding is that those plots were organized and run under a more secret program or programs. Mongoose was pretty well documented - there's a long paper trail - and I find it hard to believe that the Castro plots would have been part of it.
Harvey was associated with Mongoose. Accoding to some interpretations, Lansdale and Edwards told RFK all about the assassination plots. Possibly Lansdale briefed SG-A about it. Don't expect a "smoking gun" as to how much the Kennedys knew or instigated. The Church Committeee devoted a whole section to "Plausible Denial". (
Link )
There's no absolute caught-on-film or confession evidence that Oswald shot the President, either.