All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
If you are certain that you did not wash your ears during ghusl and did not know of the obligation of washing them during ghusl, then the validity of your prayer in this case is subject to different views of scholars. The majority of the scholars, including the Hanafis, held that in such case you must repeat the prayers that you performed with doubtful ghusls. However, Shaykhul-Islam Ibn Taymiyyah and some other scholars held that the prayers are valid in this case because when the person fails to fulfill any of the conditions of the validity of prayer out of ignorance, he is not obliged to repeat the prayer. This view is based on the verse (which means): {And there is no blame upon you for that in which you have erred but (only for) what your hearts intended. And ever is Allaah Forgiving and Merciful.} [Quran 33:5], as well as on other pieces of evidence to the same effect.
We believe that there is no harm in following the view of Shaykhul-Islam Ibn Taymiyyah in this regard, especially if you are suffering from waswaas (obsessive whispering). This is of course as long as you are certain that you did not wash your ears. If you only doubt whether you washed them or not, then you should know that having doubts after finishing the act of worship does not affect its validity. For more benefit, please refer to fatwa 119112.
Also, you are not obliged to repeat washing your feet during the ghusl if you walk a few steps to get something or the like. It is enough to wash the feet once during ghusl. For more benefit, please refer to fatwa 81405.
Allaah knows best.