First things first its Ukraine that violated the Minsk Accords, and bombed the citizens in donbass, who at the time where theirs, leading to this whole conflict when due to the violation of the accords Russias hand was for lack of a better term forced. If you will remember back it was not untill the DPR and LPR overwhelmingly voted for unification with Russia did they.
Second, you seem to be prejudging the medation China has made no statement beyond their want for peace, I am only stating that it is not the United Stateses place to be demanding any terms to a treaty let alone a mere cese fire.
https://en.wikipedia.org/wiki/Minsk_agreements Look, Russia was a signitory, and therefor a party to the agreement. There where 4 parties Russia, Dontesk Luhansk, and Ukraine, and 3 mediators, how can you say Russia was not a party, it LITERALY signed the treaty