Can visiting students can take independent study courses?
yes. Students need to contact department or make arrangements with instructor. It's outside the scope of Summer Sessions. Student needs to work with department directly and dept. would give course number to plug into system to enroll. Ultimately, it is at the discretion of the dept. so the dept. can say no.
Who/what determines the number of units? Is that also at the discretion of the dept? Can the dept. decide that the course is 2 units, or 3, or 4?
Yes-that is correct as independent study courses are variable and on how the dept. sets up the curriculum.
Would it be possible for a student to enroll full-time in just independent study unit?
Source: Avy Jetter