Avana is a bit of a cat person, she really likes long hairs

He named himself that, thus he is Tittank.

Nope, one does not harass their own employees like that. Your freeloading problem causing sister is a whole other matter.

I'd estimate her canon largest size would be around that of a building for each cheek.

Because Tenks are cute and she could apply some of her knowledge on biology and botany to help experiment with how Tenk shell compounds interact with different life, as well as possibly providing insight as to how they work since Sara is more versed in physics and particle sciences and knows very little in the biological field.

There's that one time you mentioned, but she also does it on occasion for testing purposes. She inflates very rarely so she has a significantly smaller size limit on average and that's important to gauge how different people expand or inflate in different situations.

She wouldn't do that intentionally, but if she did slip and accidentally fall onto a handheld shower thingy then she would be too embarrassed and panicky to get it out before filling the room

Okay she's not THAT small!

She lacks the malicious ulterior motives and planning of gnomes, she's too pure for that.

She lacks the hair to be a hobbit, she is smooth and clean.

She and Mikhail pool their money together so both of their salaries are enough to allow her to stockpile a lot of cheap leggings. They don't last but to be fair nothing can cover her when she grows.

Nope, still not comfortable being a human so they don't have the time to think of stuff like that. Plus those emotions are strange and scary to her.

When she was very little she ran face first into a table and accidentally spilled a bucket of permanent hair dye on her head, which also affected her eye color as well. (Ignore the fact her hair would return to normal as new strands replace the old ones, permanent means permanent)

She tends to wander around and just mess with things smaller than her, or just sit around nude to freak people out.

She's the middle ground of being just a very short human (Not cool enough to be a dwarf but not so lame as to be an elf)