His nephew looks like him so I'd say no. He's probably just from a branch family.
Yes, but she keeps throwing their sarcastic tone to Takane about him being the head of the Saibara family, and how it's a special case for him and everyone chuckles after she mention that, it's just got me thinking that maybe he's not one of them and that makes him the only Saibara, or maybe his dad/mom is a commoner with no wealth. I don't know how Japanese adopt family names. That is why I am curious about his family background.
They haven't mentioned his parents yet, so I think we'll eventually learn. I suspect one of his parents married a 'commoner'.
Is Takane adopted or something by gramps? The snobby old lady seems to comment a lot about him being a Saibara and not a Takaba.