Relative to the foreign participation, since 1981 US and NATO nations have been training students on a common syllabus at ENJJPT / Sheppard AFB, TX. In that program, all students regardless of nationality are graded and passed/attrited to the same exact standards. Also, the NATO nation students that don't go to ENJJPT, but do go to regular UPT bases, are graded and held to the same exact standards as their US counterparts.
Not all foreign training in the US is created equal.