Why the urgency to waive Favors? Jazz don't have to opt in until Jan 6th, IINM. Most free agents will have made their decisions in the first few days of free agency. That gives the plenty of time to talk to every free agent they have on Plans A-Z. And then clear dollars, if needed, by July 6th when new contracts can be officially submitted. If the Jazz strike out, Favors is a great piece to have, 1) as a player and 2) as an expiring contract at the deadline.
I'm frustrated, too, by Exum's injuries. But I don't think you can dump him without giving up an asset. Do you want the Jazz to burn another pick without knowing if they can get someone else who really moves the needle in free agency? Either Dante requires asset(s) to dump (if he never heals), or he comes back and contributes to the team or becomes at least a trade chip bringing a pick our way.
Top free agent (like Harris) wants to sign with Utah? Yes, you get an agreement on July 1st or 2nd and then start making the moves to clear cap. A few very good FA's want to sign? Evaluate against losing Favs and make those moves by July 5th.