(I speculate that Tat is from Joilant)
(I've always thought this, too.)
Maybe Leorina found Tat similarly to how Lolo found Popka? But instead of just finding her shivering in a box, maybe she was already a little thief in Joilant. Leorina just ran into Tat or maybe caught Tat trying to pickpocket her, and decided to take her under her wing as a pirate?
I dunno I'm making this up as I go. It sounds cute enough :3c