Did Imam Ali appoint Malik al-Ashtar and Muhammad ibn Abi Bakr over Egypt despite their involvement in the fitna against Uthman ibn Affan, or was there a disagreement between Imam Ali and Uthman?

Malik al-Ashtar and Muhammad ibn Abi Bakr were present during the tribulations surrounding Uthman's killing, but they did not participate in his murder; rather, they opposed it. Ali (may Allah be pleased with him) was not hostile towards Uthman. Instead, his disagreement with Mu'awiya was over the priority of exacting retribution from Uthman's killers. Ali believed that unifying the community and calming the strife took precedence over retribution under those circumstances. Ali's appointment of both al-Ashtar and Muhammad ibn Abi Bakr was for political and legitimate reasons. Al-Ashtar was an experienced and suitable leader for managing the turbulent situation in Egypt, while Muhammad ibn Abi Bakr was his foster son and a trusted individual. Perhaps his appointment also served to appease the people of Egypt, who were content with him as their governor.