Yes, I believe so.
I also wanted to ask about this, since I think "tá ... ar" is used to express need, such as "tá air orm = I need air", if I was drowning say. At least I reacall learning this in an Irish story called Calua, about a whale whose family gets killed by whalers while in school, but I am not positive.
No, it wouldn't work for that. See my comment above, idioms don't translate.
orm = on me, literally. The coat is on me. I am wearing the coat. And it is conjugated. So -
orm = on me; ort = on you; air = on him; uirthi = on her etc
I'm paying = Tá mise ag íoc.
I will pay for it = Íocfaidh mise as. - that's for later lessons.