Can't is an answer. Sasori won't send his Third Kazekage to battle him directly. Sasori will just use Iron Sand Unleash. Althought it won't penetrate Susano'o due to Yata Mirror, Susano'o won't be able to move because of it's size and Iron Sand Unleash. It will lock Itachi and his Susano'o in one place. And if Itachi lowers his Susano'o Sasori will scratch him with Iron Sand and it's over. So Sasori either waits for Itachi to run out of chakra or to lower his Susano'o.
no, can't is. "Sasori can't get past yata". Kazekage was destroyed with a single punch.
Swing from totsuka, rasengan, fireball jutsu, taijutsu, water blast from toad, punch from susano'o, amaterasu can all destroy it. A feint can kill it (like sakura did). Want to know the truth? You realise sasori is useless in this fight without kazekage. Infact, this isn't sasori vs minato/itachi. It's kazekage vs minato/itachi. Have a good day, sasori loses.
Everything else you listed is bullshit. Sasuno won't be able to move...? What? itachi ran from sasuke with ribcage susano'o. Sasori can't even get past rib cage susano'o. Gaara's sand and ay's kick couldn't get past ribcage susano'o. sasori would need ironsand
inside susano'o to even hit itachi. That's impossible if susano'o is already up. Itachi doesn't need to drop susano'o ever. He can just tier it down. A punch from susano'o is all it takes to brush that iron side away. Sasori won't get a chance to wait for itachi to run out of chakra, because the truth is he'd be on defence the entire time.
Iron sand bullets - yata tank
Iron sand objects - susano'o punch flings it away.
Sasori has to manipulate the puppet to do w.e he wants and, no, he can't fly on the iron sand/use sand orb just because gaara can. You need to know how to do jutsu to be able to do jutsu. So, what, sasori instantly knows how to use iron sand eye too? Bullshit. stop extending gaara's moves. Next, you'll say that sasori puts iron sand armor around kazekage puppet. Sasori gets raped by susano'o, totsuka, etc.
Oh, one last thing. You assumed itachi doesn't know about poison right? Well, let me give you a fact, then. Sasori doesn't know itachi has yata/totsuka. Both zetsu and orochimaru(who studies everyone) didn't know. Sasori has no way in hell of knowing this. Itachi runs of sasori.
Minato is the only debate in this thread, and even then. Sasori can't even hit him.