Molotov is voiced by Mia Barron. She sounds like a normal lady with a Russian accent, mostly. Example one, example two.

Mistress sounds like... lol me doing a really smug voice? idefk. I read all my tags out loud (Molotov too, I read in a Russian accent) to make sure they sound right, so really I just associate Mistress's voice with my own. All I can say is that she's got a really haughty, smug, sort of perpetually-entertained voice. The kind of voice you have when you don't have to worry about anything ever.