I don't think Siakam is going anywhere, but if he does, the deal probably looks something like this.

The Pacers lineup after this deal would be Hali/Nembhard/Hield/Pascal/Turner. That's really good, and a team that would be very young, so near-term picks from the Pacers would be expected to be in the 20's. The Pacers also don't own any additional picks anymore, so a picks-based package is out.

The only realistic way I could see a trade happening with the Pacers for Pascal is if Mathurin is involved. Masai has liked Mathurin since before the draft, he's Canadian, and he's the only high-value young player the Pacers have who fits what the Raps would need.

Walker isn't the prime piece the Raps would want, since the Raps would still have OG/Scottie in the frontcourt, but the Pacers also aren't getting an All-NBA'er for Mathurin, cap filler, and a couple picks. Walker seems like the best fit to fill out the package.