Okay, for this ship i will assume that they do eventually get together and get married
Who was the one to propose: I could imagine either one doing so really? Though if N were to propose, he would make it sound unnecessarily complicated because he honestly has no idea how one would propose
Who stressed more over wedding planning: Rosa
Who decorated the house: Rosa did most of the designing, but N wanted to add a lot of square/cube designs
Who does the cooking: Both, though N’s cooking skills are greatly limited and Rosa is best at making sweets
Who suggested kids first: I’m not even sure if they would have kids, but Rosa would be the one to suggest them
Who’s the cuddler: Both, N more so than Rosa
Who’s the big spoon/little spoon: N is big spoon, Rosa is little spoon.
What’s their favorite non-sexual activity: Going on the ferris wheel (not alluding to any other ship that shall not be named)
Who comes home drunk at 3am: neither
Who kills the spiders: Rosa really wants to, but N doesn’t like to see bugs killed
Who falls asleep first: Both tend to fall asleep if they’re doing something (ie, N sleeps while studying, Rosa sleeps while cooking - and sometimes N has to wake her up so she doesn’t set the place on fire)
A head canon: Rosa wants to clean up the castle, but N thinks it would be a bunch of useless work
Their relationship summed up in a gif:
Do they have any “rituals”?: They have a rematch every summer, to remember the day Rosa was given Reshiram
Who has the most patience?: N, unless it’s about pokemon liberation