I saw a very well-known actor give a panel. He said always get paid. Even if it’s minimal. I would agree. Just for self-respect, negotiate a payment. Then, you can justify writing off business expenses. If you’re not paid, you have no business, therefore cannot write anything off.
Probably your 16 and 50. The 16 will give you a really nice wide shot, and the 50 is nice for portraits. If you can, a 200 or 300 zoom is what i use for candids.