Moving away from tiers for a moment, I think Zoe is a classic mean girl who cannot cope with having any females around her who are ‘threats’. She hardly has any female friends, the ones she does have are because they’re the girlfriends of Alfie’s mates and she’s hardly pally with them.
Her previous female friends like Louise, Niomi, Tanya.. well Louise is much larger than Zoe so she was ok to be mates with as Zoe would always feel the skinniest and prettiest but when Louise started having more babies and living a life Zoe so so so OBV wants then boom... friendship dead. Tanya and Niomi had glow ups, became skinny and prettier than Zoe no longer mates with jealous Zoe who has to be the littlest and prettiest in every group.
Holly is larger than Zoe. Not a threat in Zoe’s mind.
Poppy her only female friend obvs struggles with her weight and hangs on Zoe’s every word. Perfect friend.
Let’s not get started on Dianne, beautiful, fit, successful, skilled... Zoe would NEVER be mates with her if not for Joe.
Bet she stops hanging with Maddie once her baby is born. Pure jealously.