Why on Earth would the Clintons still be friends with Kissinger if Nixon and Kissinger did actually sabotage the Paris Talks? ... That's my big flaw with that theory.
If anything, this is further confirmation of your theory? Even by the standards of politics (with all the vice, deceit, and manipulation it involves), the Clintons are a top contender for the most ghoulish political couple of 20th-century America. To borrow from Christopher Hitchens (I recommend watching the whole interview), Bill Clinton in particular can be aptly described as an "unusually ghastly" individual and the textbook case of a complete and utter psychopath.
The likes of Nixon and Kissinger are precisely who you’d expect the Clintons to keep company with.