Is it prohibited for someone coming from the Eastern Province for Umrah to enter into a state of Ihram from Rabigh or from Jeddah, and does he enter into a state of Ihram from Jeddah if he intends to perform Umrah while residing there after his arrival from the Eastern Province?

Whoever intends 'Umrah must enter into ihram from the miqat they will pass through. They should not delay the ihram until Jeddah, unless they intend to rest there and then return to the miqat to enter into ihram from it. As for someone who is undecided, they are not obligated to enter into ihram from the miqat. If they decide to perform 'Umrah after arriving in Jeddah, they may enter into ihram from Jeddah.