Eggette / Omelette - "JUST found out about Eggette/Omlette and I love her???"

The adoption angle feels a bit better. Eggmans primary character trait in the movie is being smarter than everyone else and orphaned.

Him finding a random kid that can match his wits and earn his respect enough to end up adopting her could be a cute storyline.

Or you could just go the android angle and say he built her himself