>It's pretty complicated to say the least. I was hoping I would be able to write a statement that just checked for a students existence in each subquery. I was thinking of using ICASE but I wasn't sure if I could use that in conjunction with "Where exists ( Select * from level5)".

You could use a table variable for this and then join it to the query:

DECLARE @StdLevel TABLE (StidenId int, Level int)

INSERT INTO @StdLevel
SELECT StudentId, MAX(Level)
FROM (SELECT StudentId, 1 AS Level
             FROM Level1
      UNION ALL
      SELECT StudentId, 2 AS Level
             FROM Level2
      UNION ALL
      SELECT StudentId, 3 AS Level
             FROM Level3
      UNION ALL
      SELECT StudentId, 4 AS Level
             FROM Level4
      UNION ALL
      SELECT StudentId, 5 AS Level
             FROM Level5) Levels
GROUP BY StudentId

SELECT .....
FROM ...
INNER JOIN @StdLevel StdLevel1 ON ....StudentId = StdLevel1.StudentId AND StdLevel1.Level = 1
...

Something like that.