Wasn't working until I made this one simple change
Hello. Just in case this helps someone else I thought I would post what got it working for me.
When trying out the Example project from the UE Marketplace I found that I had to remove the divide by 100 node from the LiveLink Facenode Function in the Animation Blueprint before this would work correctly.
I'm not sure if there was a change at some point or if there is a difference because I am using an iPad instead of an iphone but it worked for me.
Well that and figuring out that the fifth character in the Face ID name was an upper case I and not a lower case l. lol