Hi, earlier today my wife backed into someone and rear bumper took a light beating from ~45 degree angle. Metal is untouched.

It looks to be 4+ hour job to remove the bumper and I want to get all of the parts ahead of time.

Any suggestions as to what would need to be replaced?

Thanks!

bump

You're not going to know until you open it up.

Typically, there's a chunk of styrofoam behind it. You may have gotten lucky and there's no damage behind the urethane cover.

p.s. It's not nice to blame it on your wife.

Hitman is right ,gotta get in there- cause it would be a bad move to buy anything in anticipation , too wide range of damage,and try to return those ? The "energy absorber" on frame is plastic and on top of that, shaped styrofoam that "fills" under bumper skin could get deformed.
Tip - A-zone's have a black body epoxy that's flexible , great for plastic "skin" bumper tears ,I've used the expensive 3m (was tan) , gotta re-paint ya know.
Also the styrofoam , if gotten "deformed" - you can try that Home depot Low expanding foam in a can to kinda fill-in like bodywork so you won't have "hollows" beneath the bumper skin. Ya just trim it down with a knife when fully cured and sculpt a "best fit " for yourself