(Just what Lunabella calls her different parents, and what she does with them.)
Natasha: Mom/Mama
Once Lunabella is old enough the two train together. Lunabella trains with everyone, but her favorite to train with is defending Natasha. They're both just two badasses.
They also just spend time together. Being the only two girls/females, until Wanda, and being mother and daughter, they had a close bond. Sometimes they'd go shopping, or for lunch, or to get ice cream, or just anything they want.
Tony: Father
She helps him in the workshop. She loves to tinker, especially with Tony. She'd help him with both fixing and making new iron man suits. He'd help her make little things she wanted to make.
Tony always tried to teach her everything he knew about technology and inventing. She was such a smart kid she easily picked up things. He'd say she'd be 'the next Tony Stark', but he thinks she has the potential to be even better than he ever could be.
Steve: Dad
Running. Once she could run, he'd take her on runs. Practically everyday, Steve wakes her up early for a run. Sam and Bucky often joined them as well. She was a ball of energy so a morning run helped her be able to sit still for a while the rest of the day.
Key works being 'for a while'. She had energy and electricity coursing through her body. Which could sometimes make it hard for her to sleep, so sometimes they'd go on runs before dark.
Thor: Pop
They both had a certain love and passion for poptarts. They'd try every new flavor. They even found recipes and made their own. The first couple attempts didn't really turn out, but they kept trying until they improved enough for them to actually be good. She had a fast metabolism, needing to snack throughout the day, and sometimes she 'crashes' and passes out for a while.
Other than poptarts, they also think it's hilarious using Mjolnir to mess with people. They'd set it somewhere and wait for their first victim. People'd try to pick it up, but couldn't. After a small crowd would form, she'd go over and pick it up with ease. People's reactions were so funny, especially while she's younger.
Loki: Fadir (faðir is Norse for father)
They both enjoyed a good book. Loki would read to her when before she knew to read, and he'd take her to buy new books once she could read on her own.
The two also enjoyed a good prank. They'd pull pranks on the others. Loki's prank ideas were usually a bit more devious than Lunabella's.
Bruce: Pa
She'd help him with experiments in the lab. She actually liked it. She started doing it when she was pretty young. It started as a school learning situation, but she kept wanting to help him, so he let her. He loved having her as his little assistant. She was smart and he knew he wouldn't have to constantly dumb stuff down for her.
The two also spent time figuring out different ways to stay calm. Lunabella didn't fully 'hulk out' like Bruce, but she also sometimes needed help staying calm. When she got overly emotional her strength could get out of control. She also had anxiety issues.
Clint: Papa
As soon as Lunabella was able to hold things, Clint wanted to teach her how to use a bow and arrow. Some of the other avengers told Clint, "you can't teach an infant how to use a bow and arrow, it's dangerous!" Once he was allowed to start teaching her, she actually picked it up pretty quickly. One could say it's in her DNA. They did archery together all the time.
He also taught her all he could about basically everything he knew, including (but not limited to) bird calls. The two would constantly practice their bird calls, even making them into codes. They also sometimes mess with people using their bird calls.
(668 words. Whatcha think?)