Yes, but only if they are deducted from your payroll by your employer, which is usually the situation when you have an HSA, but not always. You won't get a FICA

Yes, but only if they are deducted from your payroll by your employer, which is usually the situation when you have an HSA, but not always. You won't get a FICA refund if you contribute yourself off-payroll, but you will get an income tax refund at least.