That question was so good for my class coz we all helped each other with, and specifically practised, Unity & Diversity Q's for a couple weeks since we thought it was very unique and we could defo get it.
I reckon you would've done well with what you stated here, but just a quick q - along with this, did u explore the DIVERSE beliefs/views of the different denominations of Christianity especially in regards to Baptism & Ethics? Because if u managed to incorporate those throughout ur response, while also fleshing out the common elements of the practice & ethics to all denominations, it will surely stand out to the markers.
Personally, my school does Marriage Ceremony & Bioethics (PJXXIII for person) so we looked at the practice's common symbols across all denominations, as well as specifically Catholic, Orthodox etc. and for Bioethics we wrote about our common teachings, as well as Catholic, Uniting & Anglican views on contemporary issues in relation to the teachings.
But yeah you'll probably do very well in the end, so don't worry.