Does this mean that whoever possesses faith weighing more than a dinar will never enter Hell, and does intercession occur immediately after believers enter Paradise or after a long period of time?

Intercession occurs after the believers have exited Hellfire and crossed the Sirat, at which point they will seek intercession for their brethren who have entered Hellfire. Moreover, the entry of some believers into Hellfire does not contradict the intercession of the believers and their bringing out of those they knew, as well as anyone who had in his heart the weight of a dinar or half a dinar of faith.