Who is the weakest here ?
Kidd has no Haki but still better AP and Dura.
Shiryu might be a future Zoro opponent so I bet he's above Kata and Kidd.
Sabo is the strongest here.
The literal embodiment of flames, possible ACoA, Observation, Flame Emperor title, etc.
I honestly see him being a possible candidate to fight Sakazuki, and maybe he'll get blue and white flames while Sakazuki gets blue magma on top of his regular Awakening stuffs.
I also see both having ACoC in the future but that's just me.