Unhinged captains are a Trek staple - and this captain was given authority to enlist whoever he wanted or needed for his mission. This is the result.
Maybe we have seen them in the background, but they are reimagined into something we can't recognize?
Well it is rather amusing, stretching all the way back to preproduction we did see what looked like an Andorian Antennae prosthetic being worked on. At least there was a lot of speculation it might be Andor- Ohh... Those clever writers.
Airiam, easy. She led the bridge resistance (several times) against Mudd, she's been placed in command by Lorca (I think she may be second officer), and as the spore drive ops specialist, she has a demanding job that she has excelled at. Whether she's a robot or an alien or both, it doesn't matter. She does her job well and she does it right and she doesn't cause a fuss. She's the most-level headed Star Trek character since Lieutenant Leslie.