Getting a fish to ride a bicycle has always proved problematic.
Too often, you end up with an oddly shaped bike and a smelly rider.

Although I have never used any of the above -
I suspect that they are neither good panniers nor good backpacks.
As panniers they have less storage and are weightier.
As a backpack they are less comfortable.

So why not just get a good pack and strap it across the back rack??

I have hiked in dozens of national parks and wildernesses - overnight -
using a pack that I have strapped onthe back rack.