As a Charger fan, I think I can tell you a little about Freeney since he last played for us.
He wasn't bad with the Chargers, he's a good situational pass rusher. He didn't get many sacks with us but he was really close a couple of times. Unfortunately, those times that he was close, the opposing QB completed a pass for a big play vs us.
I wouldn't expect him to get many sacks with yall but I think he should get a pretty good amount of pressure. His leadership should also help your defense overall. Arizona has maybe the best secondary in football so adding a guy like Freeney should make sense.
He did have an issue staying healthy, even in games that he played, he did not finish many of them so that is probably your biggest concern with Freeney. Freeney was never an iron man durable player even during his prime when he was young with the Colts so age 34, you can imagine. But assuming he will only be used in situational passing downs, he should manage to stay healthy on limited snaps.
Freeney has a great personality and is just someone that you want to root for. Best of luck with him!