Sanji has fire in his system, poison doesn't affect him much especially he won't touch Sanji
Sanji doesn't have fire in his system and speed is pointless in this fight. Sanji only has melee attacks and Magellan can surround himself with meters of lethal poison. Until Sanji gets a long-range attack, Magellan counters him hard.
And, again: Sanji doesn't have fire in his system.
especially Zoro with his speed and his swords could get damage just the same as that rust marine guy who got better of him. His far away slashes didn't stop him at all.
That scene has nothing to do with this. Zoro was surrounded by hundreds of enemies, most of them high-level marines and DF users. He didn't know their abilities and he didn't have time to figure them out either. He just tried to slash Shu (that's the "rust marine") in melee like he would any other normal enemy because he didn't know Shu had the power to grab his sword and rust it.
They extended the fight in the anime and made it absurd, but in the manga it was only a single, small panel that caught Zoro offguard.
Also, you're trying to downplay Zoro based on a "feat" from Enies Lobby when we're talking about the current Strawhats in Onigashima. You like to downplay his resilience by saying his old durability feats don't count "because he fainted to Kamazou", but you ignore his progress in every single trait like how his attacks have improved, "because he lost a sword two years ago". That is not objective nor fair.
RS is pretty sure immune given he has a sister who deal with poison. Pretty sure RS is build withstand elemental and even substance to melt or try to damage it. Doesn't make sense what your pushing as it make sense Sanji has more advantage than Zoro in this type of fight especially tricky DF users. Jimbei and Luffy also will be ones Magallen can't beat as well.
Reiju has never shown poisons strong enough to act like acid, and that wasn't even Magellan's strongest poison. There's no reason to believe RS can protect from this kind of attack, specially not since it doesn't cover Sanji's head and he would need to dive his full body in the poison to reach Magellan.
This is not "a tricky" opponent like, for example, Law, this is an opponent that you can't approach in melee or you die. Sanji gets countered hard by Magellan in a way characters like Zoro, who just happen to have long range attacks, are not.
Jinbei is also hard-countered unless they fight on the sea, in which case he could possibly hard counter Magellan. Luffy has a chance to beat him with his G2/4 speed and emission haki, but not without putting himself a lot at risk.
Loses to the first person with CoA.
Normal CoA is not enough, it should be emission CoA, since the invisible barrier around the user can potentially protect him. Since only Luffy so far has confirmed emission haki in the crew, and since he can just cover his arm and extend it instead of covering his whole body to reach him, he's likely to win.
However, Zoro can probably cut Magellan down from long-range.
Not only was Ivankov able to damage Magellan from long-range, we also know Shiryu was considered Magellan's equal back in the day and he was only a normal swordsman, which pretty much confirms that air blades from a skilled enough swordsman work on him. I believe Zoro is one.
That depends on Zoro knowing Magellan's skills, obviously. If he rushes with no info instead of staying back and attacking long-range he can get defeated, but since there are no fight conditions stating otherwise in the first post I assume that they both know how the other one fights.
