Sorry about the late reply as I haven't been on this site for a while. The Renegade's TPO body parts can be repaired though not with fiberglass resin. They require a special epoxy made specifically for bonding TPO. And the repairs must be re-enforced from behind with webbing. I only had two cracked body parts on my restoration and decided to let a local body shop handle the repair. The procedure is not much different than repairing plastic bumpers on today's cars, which any body shop should have plenty of experience.
Good luck with the Renegade. Tis a rare animal you have there.