IS Magellan a paramecia user? I'm not so sure.....
I mean think about it, what makes a Logia?
Intangibility
The ability to manipulate their "element"
Being MADE of their element
Magellan fits two of these very well.....and the one he DOESNT fit can be argued a bit (for now).
Hear me out. We've all heard the "The Gumu Gumu no Mi is a Logia!" argument, and I think we can agree that its not true. While the Gum Gum fruit IS one of the tricky cases in that Luffy IS rubber, he CANT manipulate his body and project his rubber at will.
Sure he can stretch himself, but thats simply a property of his body, he can not mentally manipulate his rubber or project his rubber beyond his body.
Now Magellan on the other hand CAN. Not only is the Chief Warden MADE of Poison he can manipulate himself to project that poison beyond his person. These abilities are the definition of Logia.
In fact, many many of Magellans moves have been witnessed by other Logia users, he can:
Throw his poison(Ace, Akoji, Kizaru)
Travel THROUGH his poison (Kizaru)
Manipulate the Shape of his poison (Ace)
The only thing thats missing is intangibility as Luffy DID manage to hit him....BUT, this could be explained by either A) The speed of luffy's attack surprising Magellan, thus not giving him time to become intangible (we saw this when luffy accidentally ran into Smoker and Ace in Alabasta...they CAN be hit) or B) Perhaps Magellans fruit is an exception like BB's
Either way if it IS a Paramecia its easily the most Logia like we've seen. The only thing missing is the ability to allow attacks to pass through him.
EDIT
Also (not that its relevant to my argument), even though Magellan isn't technically intangible, to a physical fighter like Luffy he may as well be.