I have Madeleine Backus who was a Hufflepuff and year ahead of her, so they would almost certainly have known each other. Maddie was their house prefect as well, so they would definitely have known each other and been likely friends given their backgrounds. Happy to have a long established friendship if you want to retcon that it for them.

I also have Murdock Greyback and Samuel St.John-Black who are in the ministry, although different departments.