That would be the PL-15. There are multiple contradictory claims for its range but should be higher than anything the US can use at the moment. Depending on which numbers you believe it either has a range in between the AIM-120D (only available starting this year) and AIM-260 (not available yet) or higher than the AIM-260.
I personally think the PL-15 has a range similar to the AIM-260. Because the PL-15 is a dual pulse missile.
The PL-21 long range missile should not be able to be carried internally in the J-20 because it is just too long. Supposedly 6m long vs 4m length for PL-15. Also AFAIK the Ramjet powered air to air missile is still not in service.
As for the radar, given China is basically neck and neck with the West with regards to GaA and GaN technology, I doubt there will be any significant advantage for US radar over next decade at least.