Osgar - Not really. It's pretty much all a placeholder in the off chance that someone out there might want to take on the part of having him be their family's somewhat wayward charity case.
Joseph - He's probably gained a bit of a reputation by now as a person to go through to get things done in the DMLE without having to run the gauntlet of dueling egos that the department likely is most of the time. If Joseph should need something he'd probably be happy to try to help.
Cassandra - great. Honestly, if his grandfather was a pureblood, he's probably somehow related to most of the wizarding families out there. But it likely won't come into play. Even if a Yaxley comes in. After all, bastards of bastards are to be ignored, not acknowledged.