@VIPERastronaut: Regarding Post #3, if you go into the Purdue Data Digest and look under “Applications, Admits, and Matriculations,” and use the parameters of foreign, undergraduate applicants to COE (which is how you would be applying, if I understand your original post), the recent acceptance rates have been as follows: Fall 2014, 29.2%; Fall 2015, 30.4%; Fall 2016, 29.3%; Fall 2017, 23.5%. A bit lower than the 55% acceptance rate you mention, which is the approximate acceptance rate for U.S. citizens who do not live in Indiana.
If you can apply as a resident based on your father living in Indiana, then your chances are much better.