Yes it was the plush. I chose the plush because I thought it would be a better “match” for both me and the mattress I was sleeping on and keep my head and neck in better alignment than the firm and because I believed I would like it better (you can see my comments about why I chose it in post #3 here and in post #4 here).
Yes … natural latex (rubber) is sourced from a milky liquid that comes from a rubber tree so it is a more natural material than memory foam which is made mostly from petrochemicals. There is more about the “safety” of different materials that can help you answer the question of “how safe is safe enough for me?” in post #2 here and the posts it links to.