close to zero chance of Iran getting J-20. J-20 is China's F-22, it has been banned for export. China's J-35 is equivalent to the F-35, which will be exported, but it has just entered full production and will need to fill both China's Airforce and Navy first. Pakistan will most likely get the first export. 5th gen fighters are a totally different beast than 4th gen fighters, not just in performance but the maintenance to get it in flying order is very expensive and complicated, Iran is not gonna be able to handle a 5th gen when they've been flying Cold War era American jets.

Seems like Iran is sticking to Russian aircraft, Su-35s have been rumoured for a long long time. There was a photo of a new mig-29 flying in Iran a few months ago, and Iran showed off their new Mi-28 attack helicopters a few days ago.