All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Dear brother, you have not mentioned to us the mistake that you attribute to the Hanafi School about washing the arm, so we cannot issue a ruling on your Wudu based on what you mentioned only.
As for rubbing the arm, it is an easy matter. We also noticed through your previous questions that you are suffering from OCD (whispers) regarding Wudu; therefore, we advise you to turn away from obsessions and doubts, and do not pay attention to them, and that is the best way to treat them.
As for the time of ‘Asr prayer, the Hanafi School is of the view that the time of ‘Asr prayer starts when every object’s shadow becomes double length of such object, excluding the shadow of the sun’s zenith.
Therefore, there is nothing wrong to pray with them in the mosque at that time, and the basic principle is the validity of the Imam’s Wudu.
Allah knows best.