Ice, crossover connoisseur.

Crazy thing is, Oracle didn't even have a crush on Madotsuki at first. She had a crush on Helen, who was Madotsuki's best friend, who also showed up at her confession to try and win over Helen. She rejected both of them, but then she fell in love with Madotsuki a bit after Oracle got over it. Then, Oracle showed up at Helen's confession to win over Madotsuki, and she accepted Oracle's offer.

I imagine that Grace thinks she's also from Earth at first, but then she'd ask what Earth was and throw him for a loop. They'd then tell each other about their respective solar system, and they'd realize that they're basically the same but with different names and klimaformed planets on Ariane's side. Ariane would also probably make a comment about Grace having a Vinetan accent like Elster (since Vineta is the Earth equivalent).

Also, bringing their crewmates into this, Rocky and Elster would probably have a discussion about their respective universe's technology. The conversation likely starting with a question about the translation program Grace made or the fact that Elster has robot parts, or more accurately, is a robot with (sort of) human parts. Eventually they talk about their respective ships, and Elster tells him that the Penrose uses nuclear power. Rocky freaks the fuck out about this, since his entire crew died due to radiation poisoning, so they work together to replace it with an astrophage based power source.