looks very doable to scratch-build. For the main body, 1/4" ABS plastic sheets (or 1/8" in some areas?), good saw to cut with, belt sander, portable sanders, dremel with various stone grinder and sanding pieces. Screws, nuts, and/or glue to put everything together. For the jetpack's cylinder, plumbing parts like large PVC piping, gaskets, large O-rings. ABS paste, putty, or some other comparable filler to fill in the seams. Use plastic or metal brackets to attach to the backplate. Looks like it could weigh about 4-8 lbs roughly.
If doing a ROTJ version from BF2, the chestbox could be mounted different ways - back panel with screws, magnets, velcro, etc.
Strong interior straps to support these additional components.
Good measurements and proportions are key.
Look like a fun prop to make!