She won't be able to do Palo, Remy, or even the spa at 16 as they are all reserved for guests 18 and older.
A Cabana on CC is going to be hard. I believe they all only hold 10 maybe one holds 12. Booking things for 19 people is going to be rough. I would call
DCL and see what group activities they may have. I know you can rent space on board so you could perhaps do that and then hire some characters if they are into it.