Well you should only borrow what you need. Especially of the type of loan that accrues interest.
But yes, you can return loan funds through your school for 120 days for the federal loans I believe.
Basically add up all your expenses and subtract all aid. Except work study because you will earn that and not have it up front. That should be what you need to come up with for the year, divide by two for the semester.
That should be close to what the school bills you, plus living expenses.
Yes the work study income is subject to federal (and possibly state) income tax. But if your parents claim you as a dependent on their taxes, you get a $6300 standard deduction on your tax return and if you make less than that, then you don’t owe any tax and might get a refund if employer withheld tax from your paycheck.
Work study won’t impact FAFSA EFC because it is income from need based employment.