I'm going to ask a girl that has a crush on me to set me up with her friend
Don't you think that's messed up? Why would you specifically ask her to do that?
The friend is a hot babe who I want to take out.
If you know that this girl likes you, you should not ask her to set you up with someone else. It is just going to hurt her feelings.
I'm just trying to do her a favor so the least she can do for me is to hook me up with a model.
You won't be doing her a favor doing that. If you really are interested with her friend then go ask that friend out and leave the other girl alone so that she will not be involved with this. She may eventually find out you dating her friend, but at least you did not go to her and made it hard for her to set up the date with her friend.