>>10449
I initially thought of there being laws against what is essentially cloning, and it being the reason why Alex freaked out, because if discovered there'll be a mandatory disintegration of one of the Alyssas- to law it doesn't matter which as they're pretty much identical pre-separation and accumulated very little difference post-separation.

Now you say that, maybe instead of disintegration there's a merger, which neither side desires either- small one doesn't want to stop being a separate mind, big one doesn't want a mishmash of memories and personalities (which changes when she ages and with their different lifestyle) in her head in addition to that. Or even just a fine neither of them can pay and that will take toll even on their rich parents. Either way, both Alyssas and Alex are agreeing that the duality should not be discovred, and keep little Alyssa a secret.
Keeping her in compact state can be viewed as acceptable by all three sides as a temporary solution to hiding her during the trip, but it extends for a while after it as well (as she needs to regenerate half of her mass while being somewhat underfed because she's fed leftovers snuck off the table), all while they take care of her like she's their newborn child. This brings big Alyssa and Alex closer together.
She eventually grows bored of this lifestyle and as soon as her fingers grow she, being juvenile, starts pulling pranks on them two- Car Fight-worthy pranks, of course, like placing a music player in her sister's belly, with a timer so it starts working during school; for which she gets punished in a Car Fight way as well as the two really take a role of her parents.
What's next? I don't know. They may appreciate having a dedicated surgeon at home instead of having to patch up each other, for example.

I probably won't write anything for this arc, just throwing some ideas (though I do have an idea for a standalone story that'll benefit a bit from having small Alyssa's assistance but it's not crucial to it). Thanks for grounding me in this universe's roots so I can correct my ideas a bit.