For largest OEM components you're on the right track.
Explorer/Mountaineer had the largest SLA front swaybar, but I can't tell you the size. Consider size and weight, IIRC some of those bars were solid and others were hollow, but I can;t recall the year it changed. Obviously the solid bar is going to be stiffer, even if it is slightly smaller.
Bronco II 1" rear sway bar would be the erasiest to fit in the rear. There may be an Explorer bar that is about the same size, but differences in the suspension make it less desirable if not completely unusable for a stock Ranger rear suspension.
Don't forget to check the aftermarket for bushings if necessary. As I think was notedf above the BII used a 7.5" rear axle while your truck most likely has an 8.8" axle. IIRC the BII bar was mounted to the axle using u-bolts, it didn't have welded on mounts like the later trucks. I can't remember about axle tube sizes, but the 7.5 hardware may not fit around the 8.8" axle tubes. Companies like Energy Suspension sell universal mounts that will fit.
FWIW I've got both an Explorer front bar and a BII rear bar to install on my 99 when the time comes. I think that I was planning to use Energy Suspension bushings/mounts to attach the BII bar to the original 8.8 axle mount points.
Theres been a lot of discussions about sway bars down in the 2wd suspension section over the years, might be worth taking a little time to go search for it.