Mart the reason I'm on here is to find out what I have.There's no thumbs up at all,sorry it's not Tiki,I have some Tiki items and Polyneisa.I don't need anyone to agree with me I throught this site was for asking and getting answer.
This site is NOT just for asking and getting an answer. It's about give and take, sharing and exchange. As far as I know, no one here is getting anything for helping except "brownie points". If so, I'd quit my day job ha! So, you may help as well on any post you choose. We would appreciate that because no one here knows everything.
The other thing that really helps is when sizes, dimensions, and past research findings are given accurately. That way, we are not spending our time wastefully. Another words, we don't like to do what has already been done. I realize that some of your items have been online since 2012 and that must be frustrating...
Now about this cup, you originally said you have a book with the same face and arm position. Perhaps, you could share that with us. You also mentioned it might be a child's burial cup...why? I have searched Mayan/Aztec burial cups and don't see any metal ones like yours. You also don't seem certain about the size and the item is in storage. It would help to know the correct height and diameter in order to help you.
I've enlarged and relooked at all your photos. In my opinion, those thumbs are definitely up and the so called "cup" is NOT a cup but rather an artistic texture of the clothing. What you are calling a cup is actually as tall as the head....
It may just be that this item is a handmade repousse copper/brass cup.