Well, there is no such thing like a "frozen ATPL" in the US (FAA system) that's more a European (EASA) thing. Which basically means, that one has passed the EASA ATP theory exams and holds a CPL/IR. Upon reaching 1500 hr (ATP requirements) the ATPL is active.
There are flight schools in the US which offer training according to both syllabus, FAA (US) and EASA (EU) both can be done at the same time, or combined with each other, if one desires to do so. In the end the candidate will be issued two independent licenses (FAA and EASA), which in my opinion is a smart way to do.