I think those players were left for a reason though. They were all promised a shot at joining up with Lebron/AD. It wasn't a random occurrence.
Sure they were. Which is why he was able to put the roster together relatively quickly.
That's where Pelinka's backup plans came in (which what Kobe said about him). He knew he had to wait for Kawhi's decision. But he also knew that he couldn't afford to be left scrambling if Kawhi made the wrong choice.
So, it looks like he looked at who was likely to be available, contacted those players agents and just had to finalize the deals when Kawhi chose incorrectly.