I think this topic came up a while back, and I don't remember if there was any feasible option that didn't involve removing the stock bumper cover, or modifying it.
The OEM tow hooks bolt into the bottom of the bumper frame, and extend sideways. It could be possible that the Envoy bumper cover wouldn't interfere with them, and just cover them up. Meaning you'd have to remove the cover to use them, but you'd at least be able to use them. I picked up a set from a friend that swapped to an MDB Fab steel bumper.
They are recessed in the TB bumper cover openings, which makes me think they'd sit behind the Voy cover.