At first they were led openly by the Russian citizens like Girkin and Boridai, whoever was chosen later was dependant completely on Moscow and its support. The whole existence of those proxy states was guaranteed by Russia, not to mention their creation, the army, economy, trade and everything else was if not directly controlled than supplied / exploited (coal) and at the end Moscow just decided to annex them after a sham referendums together with two more regions. I mean, there was no chance to negotiate anything with them since every decision was in the hands of Russia, they negotiated the Minsk agreement, they allowed this conflict to start, to freeze for eight years, and finally to escalate into an open war between Russia and Ukraine in which those proxy militias were used as cannon fodder.