The Hawks are looking to acquire Siakam, but I don't think that will happen. In this scenario, they pivot to an OG trade.
For the Hawks, they get an elite wing defender, who can combine with De'Andre Hunter, Capela/Okongwu and Dejounte Murray to provide as elite a defensive group as you could realistically put around Trae, while adding another effective off-ball weapon on offence who fits as a great third option.
For the Raptors, Griffin and Bufkin are the exact type of young guys they were looking to acquire at the trade deadline in an OG deal. Bufkin was a guy the Raps were interested in at the draft, until Gradey dropped to them, and Griffin is the son of former assistant coach Adrian Griffin, who also fits the brand of versatile floor-spacer they need.