I think Ewers will stay as he is still so young and all he needs is 1 year of playing to be a top pick. I do think Miller and McCord are likely to transfer as it's unlikely they get any real playing time.
Our comp pick this year will be after the 2nd round - they rotate every other year for the teams that qualify and under the current system I believe we cannot lose our comp pick, so the lost pick would be our 3rd round pick.