"It doesn't look good on you to be seen with him" is actually quite common. I hear many say sentences like this, but there are always alternates such as, "It doesn't look good for you to be seen with him." or "It doesn't look good on your part."
The other two sentences do not make much sense unless you were to revise them.
For your second question, I am actually confused about that sentence. It most likely means her overall plan for using her money to buy costumes?