I don't think comparing Ariana grande when she was on Disney to what she looks like as a pop icon today is a good example of black face. On disney, they dyed her hair red, as a child she probably wouldn't go tanning, and as a child it wouldn't be appropriate to wear adult-styled makeup to try to look sexier. Today, Ariana Grande is an adult, she should be able to straighten her hair, get a tan, and wear makeup without a bunch of mostly adult caucasion men judging her for it.
The supposed blackface photo of "Ariana Today" is what many Italian American people with tans and makeup look like.
I'm sure there's some crazy ass people on Instagram trying to look black or be black, or what have you, and that's wrong and weird. I don't think Ariana Grande fits that description, though.
With Kim Kardashian... I dunno. Yes, she looks very different than she did when she first became famous with that porn video. She's had a lot of work done to remove a lot of her Armenian features. Now, I'm against cosmetic surgery for myself and I really hate the culture of unneccessary cosmetic surgery because I see how it impacts people like my wife who are constantly critical of their perfect features because that's not what the Housewives or Kardashians look like, but... I'm not going to judge someone who feels insecure or feels like they need to get cosmetic surgery to look however they want to look. If Kim Kardashian feels better about herself with thicker lips or with less Armenian features or whatever the heck she's had done, then whatever, it's not my place as a middle aged overweight white guy on a videogame forum to criticize her for it.