Clergy housing allowance and SE status for hospice chaplains

by Nicky
(Camarillo, CA US)

I currently work as an ordained hospice chaplain and the scope of the work qualifies me to receive the clergy housing allowance for ordained ministers.

My questions:
--Can I claim designated housing allowance with a letter only (so amount necessarily reflected on W-2)?
--Do I need to be in designed Self Employed Status to receive the housing allowance (e.g. the employer is NOT paying the employer's share of SS and I am not having SS deducted in my paycheck)?