Deidara can avoid the bijudama thanks to C2 and spam bombs(C3 would be a big problem for bee).
Not sure about sasori but i think he can fly too or he can be with deidara.
They're not avoiding something thats the size of mountains. Thats also assuming Deidara starts off using a bird, though If you want to saythat then I say Bee starts off with Bijudama which is faster than creating a bird and getting up in the air. Sasori also has to get all his puppets out before he can do anything, the poison will also act slower since the 8 tails is much bigger than a human.
Not a chance. As Gakido already stated, that poison will only work in a much higher dosage against the Hachibi. Bijudama potentailly takes out both of them. If Deidara manages to get in the air, then Bijū Hachimaki takes care of him. Or Bee can start off with Hachimaki to avoid being affected by poison.
No Suigetsu took the majority of the blast, he's lucky that storm cloud ravine is surrounded by water or else Taka would've died.Deidara and Sasori don't have that type of defense which can sponge the blast, maybe Deidara can use his mole jutsu but the Bijudama can easily destroy a large portion of the ground.
Sasori solo's high diff and Deidara can potentially solo (since I saw some arguments that he can or cannot). Its funny how you gave Bee knowledge because its obvious that Bee pretty much loses low-mid. Now it just became high diff-maybe extreme dif.
Both Sasori and Deidara can either redirect the attack as much as Pain can to a charging TBB:
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(Except Sasori uses Iron Sand)
Also Deidara's explosions, which had the potential to turn a whole island around: