Russia was not a direct negotiator, but they were a party to it as the official mediator, and the unofficial force behind the DPR and LPR and acting as the guiding hand for them to exert Russian influence.

It may be technically correct, but its disingenuous to say that Russia was not a party to those talks. In the end, Putin was the one to say that the Minsk Agreements "no longer existed", not someone from the DPR or LPR, when the Russian Duma voted for annexation. Both Ukraine and the separatist groups may have violated the ceasefire, which pretty much everyone expected, with both sides being jumpy and having itchy trigger fingers, but it was Russia that chose to end them.