I don't know who specifically the Clippers would target, I just think if they put a 5th overall pick on the market and give teams enough time to outbid each other, the final price is going to be quite high. Cleveland trading Jarrett Allen has seemed likely for a couple seasons now and now that the Clippers have Darius Garland, it might make sense to reunite him with a former teammate. That would be my best guess. Allen's production has fallen off the past couple years. He's not better than Sabonis but he plays a little more of a traditional big man role.
In terms of a hypothetical Chicago trade, the trouble is even if we take Pat Williams and Isaac Okoro from Chicago that only adds up to $29.8 million so somehow they'd have to add another $15.6 million or close to it to make the deal legal.
Their payroll is pretty thin on big contracts after all the expiring contracts come off their books at the end of the season. We're looking at a 4 for 1 deal just to match salary at which point Chicago would only have 6 players signed for next season. They'd have to
really want Sabonis, and maybe they do. This summer's free agent class looks pretty awful-- I'd personally prefer to keep my lotto pick and lock in another cheap 4 year contract if I were in their position -- but historically that franchise tends to spend their money as soon as they get it and there was a rumor that Sabonis was on their wish list.