Hi, I'm a systems administrator from the US. I've worked with PHP-FPM for several years now. You also should be able to use mod_fastcgi with an 'external' directive, as that will rely on an external FastCGI server (i.e. PHP-FPM), and not spawn an additional process manager. I'll still do it your way, but it's food for thought.
Thanks for your considerations,
Aaron