1/4th Shimotsuki, assuming his one grandma was pureblood Shimotsuki.
1/4th Roroanoa, assuming his grandpa was pureblood Roronoa.
1/4th criminal bloodline which can belong to Roger, the Pirate King.
1/4th to the bloodline of whoever that criminal got pregnant. It can belong to Rocks' daughter.
So, Zori might end up a mix of Shimotsuki, Gol D, Rocks D and Roronoa.
Funny how Oda leaves an opportunity to have Zoro go from nobodies to most famous bloodline mix.
His Roronoa name would be the only one without fame.
A name that Zoro will take to the heavens and surpass all other names.
Either way, Zoro's name reaches the heavens.