I'm thinking it'll be a split elimination, one from each team. The rules were one elimination from the popularity votes, with each winner from the six contents earning +15,000 votes. (I'm assuming everyone on the team wins the bonus, not just the singers for songs with a subset.) Chapter 92 was the last time I could see the popularity rankings, and Hitoe is 26K from the bottom (above Koyuki and Hibana), though those numbers don't account for IdolFes popularity shifts. So it's possible she could lose via the popularity vote.
The second elimination was "whomever was deemed least fit for a potential group" (Ch 81, Pg 10) but I didn't see any obvious troublemakers in this round. Anon would've lost on this criteria in round 3, but she's not been much of a presence in round 4.
In terms of who is finishing their character arc (like Michiru did in round 3), I don't see a lot of obvious contenders here. My gut points to Hitoe who seems less into it than the rest of the White Stars, is young enough to have another shot, and also had that bit with her roommates leaving her. Attention on the Black Star side jumped around a lot more outside of Uraha and Karin getting a lot of focus - but I think that's prepping them for promotion more than anything given Uraha has done quite the U-turn from last round in going all-out to help her team this time. My guess would be Koyuki since she's had a few bits with ominous foreshadowing that her performance isn't going as well as she'd like. Amon, Tsumugi, and Shiori have barely been a presence this arc, so it'd be weird to axe them offhandedly. Hibana is a big question mark because she is technically ranked last, but I feel like she has more character development to come.
