Remove rear bumper from van to replace jt bent

You don't need to remove the rear bumper cover to remove the tail light units. See the link.
Chevrolet Impala 2014 2018 Tail Light Housing Removal

Most van bumpers are usually mounted from either underneath or inside the trunk. It can depend on whether it is an impact bumper or just a decorative over cover. It will probably be bolted through the rear floor or through the rear skirt panel fixed from the inside, under the body. Some are even bolted directly to the chassis rear end.

Sara, 1989 GMC Suburban front bumper removal. Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
How To Install Replace Bent Rusted Front Bumper 1989 99 Chevy GMC Pickup...
Grille Replacement 88 98 Chevy trucks
1989 Chevrolet R1500 Suburban Parts NationalGMParts com

Support the bumper with a jack, disconnect any electrical wires to license plate light, then loosen and remove the bolts that hold the bumper to the frame. Slowly back the jack up and lower it so the bumper can now rest on the floor.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/michael_2496c4f07ad24453

sounds like the bumper mounting plates are bent

The bars are likely part of what is called your core support. They are structural items needed to maintain the dimensions of the fit of the rest of the front end parts.

I am doing some minor customizing on my 2010 Chrysler T&C van. I want to remove the rear bumper cover, cut 6 openings and install a tailgate lightbar. I saw an excellent video by mamachanic but can't find it again. I do not ikntend to spend more money, as this project has cost me enough already.

Depends on how baddly the whole car is bent and how much you pay your self. You can do it, and if it's bent bad enought that you can't expect to pay mor than flat rate anyway because thier not just changing the bumper cover and or the bumper core and or the bumper core supports and or painting the new bumper cover and or replacing or straightening the care and even pulling the frame.. Most body shops and dealers will estimate this job but they have to see it because of the stroy I just told. They most often estimate for free as your insureance companies adjuster wight also. They may even come to your work or home to see the problem. If you want to keep the insurance man out of the loop then go to an auto parts store that sells auto paint and supplies. They'll tellyou about their customers and what to expect from them. and you'll hear alot of different prices, including look good or look good and be good and strong, all the prices wil be different.

Junk yards are wonderful for cosmetic parts. Especially on a van known for having transmission problems. Should be plentiful.

It's not hard with exsepton to the condition of the bolts, the easiest way is remove the bumper with brackets and bumper together. I would get new bolts for replacement.