There'll be more analysis of this in the coming weeks, but I saw early suggestions that perhaps the Raptors could get #3, Anfernee Simmons, and maybe another part or two (some people suggested Shaedon Sharpe but I think that's mostly 'derpa der we want Canadians' wishful thinking) for OG or Siakam.
I would drive Siakam to the airport for a deal like that, even without Sharpe. I like him, he seems like a good dude and he had a great role to play in the championship team, but he's a complimentary piece on a good team getting paid a big fat max contract. I'm more hesitant to let OG go but being able to build a core out of Scottie, the #3 pick, the #13 pick (a knockdown shooting wing would be nice), OG (or I guess Siakam) and maybe one of VanVleet or Trent sticking around with some other complimentary pieces would be a nice way to kick start the next era of Raptors basketball.