It seems they can in fact occupy themselves quite happily until they are ready to sleep.

Always a benefit.

Ashes sleeps well.

 - And the middle of the next day, while September's out at school, something made of smoke slides in the cracks around the front door and reforms as a tiger.

-that is an Anakin-tiger.

She rears up, unlocking the door with a paw (and some oddly firm smoke), then notices Elesse. 

"Hi!" she chirps, pulling the door open. "Didn't know we had guests."

El pokes her head out in time to see Ruby opening the door from the wrong side.

"I know you have the concept of knocking in your world, too."

"I," she says, with much dignity, "Lost my keys."

"And I suppose you dropped your ability to bang your paw on the door in the same place?"

"Yup! It's a very hard skill. Tricky to keep." She makes a noise of triumph as she figures out the latch and wrests the door open for Ellie.

"She always gets mad at you when you do this, like I was just about to say," says the cat-shaped electricity that walks in. "And now she's going to get huffy and not offer you any of that tea."

" - Awwww, but I like tea."

"Then you should have thought of that three minutes ago. Let it be a lesson to you. Anyway. We have guests. Two new alts of us, a September, and September's hypothetical twin."

"Hello," Elesse says, with faint amusement.

"Oooo, alts!" she says, the tea question apparently forgotten. "I'm Ruby - a Panthera, same as Bellona. Which're you?"

"My name is Elesse, a Lightning as we call those such as El and myself."

She tilts her head. "'We'?"

"There is another group of we alts kicking about the multiverse. I became separated from them some time ago, lost in a world hostile to extraction by outside forces."

"Oh. That sounds unpleasant."

"The company made it less so."

She nods, leaning against Ellie. "Makes sense." She turns to nuzzle Ellie. "This's my girlfriend Ellie - unless we're doing formal introductions..." Her voice sounds teasing.

She baps Ruby on the nose. "The impertinent lout here is Ruby."

She wrinkles her nose. "Aw, you don't like your title?"

"You're too clever for your own good."

She sighs, dramatically. "Okay... Mystic Storm of Feline Destiny Nyx."

She darts out of bapping range as she's speaking.

She hisses and arches her back dramatically, wild sparks flaring off, before darting playfully at Ruby.