Did gamzee make terezi kill vriska because she killed tavros?
Gamzee set it up to make it “look” like Vriska was also the one that killed Equius and Nepeta making Vriska seem more dangerous than she was. He also took her communicator glasses so Karkat couldn’t tell her that he was on the loose. He even wrote Terezi a note pretending to be Vriska telling her to come up to the roof.
So no, he didn’t make Terezi kill Vriska but he’s definitely the reason she did.