Thanks Marker! Appreciate you taking the time to spare some good info!
Talked to South Florida FSDO and to the FAA at Oklahoma. No need to renew my IR as it will be issued together with my FAA ATP eventually. Only need to have the ATP license and medical valid.
Regarding the verification of CAAC issued licenses, if anyone is interested, the FAA told me that thay are usually pretty quick in replying and they´ll verify your ATPL within 2-4 weeks as long as it´s a stand alone license and not issued based on your original one.
Cheers!