What is incumbent upon one from Jeddah who, after Hajj, omitted the Farewell Tawaf, thinking that only a traveler performs it?

If you perform Hajj, do not travel to Jeddah immediately after your Hajj until you have performed the Farewell Circumambulation (Tawaf al-Wada'). If you travel before performing the Farewell Circumambulation, you must offer a sacrifice (hady) to be slaughtered within the Haram (sacred precinct) and its meat distributed to the poor, because the Farewell Circumambulation is obligatory after Hajj, based on the general meaning of the hadith of Ibn 'Abbas, may Allah be pleased with both of them: "The people were commanded that their last ritual with the House should be the circumambulation, except that it was lightened for the menstruating woman." (Agreed upon). You must also repent to Allah for departing before performing the Farewell Circumambulation.

If you are unable to slaughter a sheep due to incapacity, then nothing is required of you, and you are not obligated to fast. If you are unable to offer the expiation, then repentance suffices.