Your GPA & DAT and other things u have done as a whole will play a key factor in determining ur admission.
As one of letter is required from religious leader, I strongly believe religion will play a significant factor.
But, I don't think u will be rejected just because u are not an SDA member.
With a common sense, if two guys have the same stat, I think they will prefer someone with more religious faith. (Assuming other things are difficult to compare for selection!)
However, all of these are from my guessing.
One additional rumor I heard long times ago is they don't consider non SDA members. In other word, it is difficult for Non SDA members to be accepted unless they have outstanding stats. However, u never know~