When the dev said he made the schedule for underwater station, we can see the detail in story:
The redhead said she has training at morning, so at the morning she showed up with Iris along in holo room and uses the VR, after breakfast in mess hall.
It proved that she is new recruit in underwater station because she was doing same hand signs like Iris, maybe remote controlling the droids or some other devices.
Susan said that MC needs to get access to Mainframe via Pixie, so sometimes Pixie was inside the Mainframe room alone or with Megan. At morning, she went to bathroom with Lexi. At night, she had some fun time with Lexi in holo room. Meaning she had strong relationship with Lexi, so MC had spare time with Redhead.
When Pixie and Lexi were in holo room, Iris just stood aside as supervising, so these two are old members.
Redhead didn't have good relation with Pixie and Lexi, which can be seen on her face while in lounge.