ngl it makes me really happy lin and su are in their hogwarts house colors in the show
and yes those are their houses suyin is an excellent slytherin and lin is basically the huflepuffiest hufflepuff to ever huffle. lin would play keeper and su would be a seeker. lin would be prefect every year she could but not head girl, suyin would never be a prefect but would get head girl 7th year.
also bumi would have been gryffindor, kya gryffindor or ravenclaw, tenzin would be the other hufflepuff prefect