Sure a non-roots question, but WPML and Post 2 Posts have been a long time in the list of Roots Recommended Plugins (this list has gone now from the website…)
I’m curious, how do you manage to integrate post 2 posts in a multilingual WP with WPML/Polylang? Did you find a way to maintain post relations between traslations of a post without having to re-assign posts in each traslation?
As I’ve read, Scribu is not interested in modify the plugin to make it compatible: http://wordpress.org/support/topic/plugin-posts-2-posts-wpml-support
And the proposed solution, P2P-WPML: http://wordpress.org/plugins/p2p-wpml/ doesn’t seems to work for me. As far as I know, post 2 post relations are stored in the database, so there’s no way to duplicate them when you make a traslation of a post, as you do with taxonomies or custom fields. But maybe I’m missing something…