Lumity is just greed to me... I have no thoughts other than consume–JOKING:
• Amity is the driver and Luz the passenger seat princess
• Amity is a BIG teaser. Fingers hovering around Luz's neck, casual stares at her lips and knowing smiles, etc. THAT GIRL KNOWS HOW TO FLIRT.
• Both love to show off each other. They are so proud of being each other girlfriend and are constantly bragging how cool the other is.
• Amity sleeps a lot and Luz is a morning person.
• Luz LOVES to play with Amity's ears and that makes ams so flustered.
• I think Luz likes to make handmade small gifts. Like, they are on dates and while Amity is yapping Luz is making her some paper animals, assembling jewelry or arranging her a bouquet of flowers she picks up on the road (they love taking walks too). So at the end of the yapping or when they reach home Luz has all these things made already and she gives them to her. Amity of course keeps them all in an special showcase.

Haven't put too much thought about it since I believe they would be very cheesy with each other in any form, but like in a daily basis I think Viney is gift giver and also fits the acts of service category, she bringing groceries, taking her out to places, if Emira liked an specific flower Viney will plant them in their garden, if anything needs fixing she would repair it for Em.
Meanwhile I think Emira is very touchy and she loves holding hands hugs, rubbing her cheek on Viney's shoulder, casual kisses, doing her hair or fixing her clothes if they are going outside, those kind of things.
Also I think they are bery good listeners so you will always see them chatting around, very close and comfy with each other. Nobody invites them anywhere because that woul mean seeing them sitting on a corner and talking to each other forgetting whatever and whoever is around lmao.