No John Lennon. Actually there was this YouTube video of these sisters Lennon and Maisie. They are amazingly talented but I saw that name and thought, how cool. My hubby picks middle names and he does the family thing. His moms middle name is Zoe.
My favorite of your choices is Zoe Lennon. It sounds very chic. I also like the idea of Winter Zoe nn Winnie. Very cute!
My ranking is...
1. Olive Zoe - I love Olive. It's 10 times better than Olivia. Great combo.
2. Zoe Winter - Love it.
3. Winter Zoe - Nice combo.
4. Zoe Lennon - I like Zoe better than Winter but i'm not loving Lennon.
5. Lennon Zoe - Lennon is a little too matchy with your son's name.
Liam and Olive are just so adorable together, so my first pick is Olive Zoe. My rankings:
1. Olive Zoe
2. Zoe Winter
3. Zoe Lennon
4. Winter Zoe
5. Lennon Zoe - I agree that it's matching with Liam and will likely be interpreted as a boy's name. Plus, most will think you are honoring John Lennon, which it sounds like you are not