With regard to that whole ICAO minimum thing: I believe that has to do with being able, with the blessing of the ICAO, to operate a commercial aircraft internationally. I believe thats why most (if not all) regional carriers require that pilots have 3000TT before they allow a captain upgrade, because otherwise the company can't let u fly an international flight. You can command that CRJ domestically with just the ATP mins and type rating, but you can't fly it over the border into Canada, for example.

If any of that was incorrect, let me know.