I have the same vehicle.
What I would do first is hook it up to an OBD2 scanner and check for codes. Also call a dealership and have your VIN handy, ask what recalls need to be performed on that model. Ask if any have been done on that VIN. Mine had 4 outstanding, one involved the rear handbrake not securing correctly. Recalls need to be fixed by the dealer for free.
After scanning for codes, check to see if any relate to your transaxle or transmission. If no codes, good. But check anyway.
There will always be some play in the prop shaft. Get up close to the u joint and rock it there, see if the caps are loose or there is excessive wear there. if there is replace it, you have nothing to lose by doing that but everything to gain. See if that changes the sound.
Check for fouling at the brake rotors, and check drive shafts for fouling also.
It is possible that incorrect wheel alignment that caused your inner edge wear, has also caused your uni joint to wear out.