Yes I believe that there are agents available to check in passengers at AA 4 hours before a flight at CDG. The agents are typically contract people, probably not specifically AA staff though I am sure that there are at least some AA supervisors available.

The 4 hour suggestion comes directly from AA. Passengers with status of some kind and who receive special handling will not need 4 hours but not everyone flies first class and CDG is, in my opinion, not the airport at which one should push the time envelope.

I personally would not feel comfortable with a 3+50 connect time at CDG using separate PNRs. However, everyone has his own individual tolerance for risk.