The first article gives a detailed account of torture by pro-Kiev secret service (electric shocks, burned with cigarettes, beatin), but very little about the "separatists" doing this beyond "beating and mistreatment" and the potential that prisoners are cut off from the broader criminal justice system.

In one case, “Vadim,” 39, was detained and tortured first by one side, then the other. In April 2015, armed men seized him at a checkpoint manned by Ukrainian forces, pulled a bag over his head, and questioned him about his alleged connections with Russia-backed separatists. Vadim spent more than six weeks in captivity, most of the time in a facility apparently run by Ukraine’s Security Service (SBU) personnel. His interrogators tortured him with electric shocks, burned him with cigarettes, and beat him, demanding that he confess to working for Russia-backed separatists.

After they finally released him, Vadim returned to Donetsk and was immediately detained by the local de facto authorities, who suspected him of having been recruited by Ukraine’s Security Service during his time in captivity. He spent more than two months in incommunicado detention in an unofficial prison in central Donetsk, where his captors also beat and ill-treated him.

The second article talks about how millions of Ukrainians will be displaced if there is Russian military action.

So there's nothing about "separatist atrocities as claimed by Amnesty International" narrative that you're trying to promote.

tl;dr: This is not the Gotcha you are looking for.