Hi,
since WPML single post layout is closed, I wanted to post a follow-up here, hoping a staff member can transfer it to the original topic and delete this one.
Translating a Single Layout is actually possible with WPML, at least in my user case:
I used ACF to create all the content fields for the layout, including images. Once you’ve installed the WPML ACF plugin, and configure that plugin to use the same ACF Fields on every page, the Single Layout works perfectly!