I would recommend keeping in mind that the オネエ was used by Mimi as an insult, so it may not reflect what the teacher actually is.
Also, the TZdY version fixes all the translation mistakes.
She does look a lot like a crossdresser in anime, though. Like the Kuragehime guy, for example.
It's pretty common to make characters like this being tall (since Japanese women rarely are on that height) and a "scary face". Also, the way she acts is usually a stereotype for characters like this. You can see Cagliostro in the latest Symphogear, or even the guy in Kuragehime.
Sure, she might not be a crossdresser or trans, and the reason why Mimi called her that is that she has those traits.
I guess that's the risk in translating on-going stories (and only one chapter out).
Another part that could be a problem is when she talks about the MC "smelling like a mother". When I read, I thought maybe she was saying: "Like Mama", as in an actual person. It could be either though, and in this case, it's not a big problem.