I'm sorry, last I checked, Steelceus only have three main variants. CM (probably most common and viable), Xern counter (uses Defog or T-Wave), or SD (which is uncommon). The only Poisonceus I've seen is SD.One of the things that make FEAR not very good in any tier is the amount of support needed to pull it off (e.g. accounting for hazards, obvious threats). Off the top of my head, Arceus (STEEL, POISON) formes use Substitute a lot, but there are probably others, at least some of which threaten Magnemite. On a side note, while this is kind of a summary, generally almost all teams have a way to deal with Fear pokemon.
Like Zangooser said, if Magnemite is ranked, Aron should be ranked. They're basically on par with each other, and are bad for the same reasons.
Try to clean up your posts a bit. You always try to cover every topic concerning the mon, but not in detail, which makes your stance on those parts a bit iffy sometimes. There are also some unnecessary parts of your posts usually, it makes the post a bit harder to read.
No comment on Glalie because never used it before.
As for this quote: "No comment on Glalie because never used it before."
Does that mean you used Aron and Magnemite before? lel.