I had panama red growing down here for a while. It use to be common in the nursery trade but I haven't checked in a few years.
It's my favorite passion fruit, with 2 crops a year, one in winter and one in summer. Self-pollinating, high production, and pretty sweet.
I never measured the brix but it is sweeter than things like starfruit or dragon fruit for sure.
I wouldn't be surprised if it could reach up to 21.
I would highly recommend this variety if you want a passion fruit.
Can't speak for the rest of them though.