Do all the students who score more than the BITSAT cutoff marks get into BITS Pilani, or does rank also play a role in the selection process?

To be eligible for admission at BITS Pilani, you will first have to meet the minimum eligibility criteria. After that, you are eligible to sit for the BITSAT examination. 

Each year a certain cut-off mark is decided depending on the number of students appearing and the difficulty of the questions. Once you get a score above the cut-off marks, you will be eligible to sit for the counselling process. This is where the actual selection takes place. 

You will be asked to give your preference for campus and engineering specialization. There will be multiple rounds of counselling after which you will be allocated your seat at one of the campuses and your engineering major based on your marks and preference list. If you do not like the campus or your major, then you can opt for the next round of counselling to get your preferred campus and major.