Arabic TV series show Jews fighting alongside the Muslims in the battle of Badr

Q: In the Arabic TV series about Omar Ibn Al Khattab, a Jew is shown fighting along with the Muslims in the battle of Badr. Is there evidence for this having happened in reality - did a few Jews participate on the Muslim side in the battles of Badr and Uhud (i.e. without first having converted to Islam)?

Washing the limbs of wudu without wasting water

Q: When I make wudhu it takes too long at times as I feel I am not wetting or covering all parts of the limb I am washing. This is also causing the wastage of water. What can I do to ensure that I do not waste water and over wash? If I rub water over my arms or legs 3 times (and try to cover all areas of the arm or leg) but not every single hair gets wet will this count as still being wet and my wudhu accepted? I would say my arms and legs take the longest.

A few questions regarding purity

Q: I have a few questions regarding purity. I would appreciate  a response.  I am subject to whispers from Shaitain, and want to understand these matters properly so I can confront this issue.

  1. How can one use water to clean themselves after defecating in a modern toilet without getting splashes of water on themselves?  I place toilet paper in the water, but water still splashes onto me.  I often shower the lower part of my body after defecating to be precautious, but I am torn between the feeling that I am wasting water, and doing something most people don't do on the one hand, and the desire to be clean without doubt on the other.
  2. To clean a garment that has urine or sperm on it, is it sufficient to wash under a lot of running water a sufficient amount of time, or must  it be washed and wrung three times?
  3. When cleaning clothes with najasah on them in a washing machine, what if drops of water from the first cycle splash onto the inside roof of the washing machine, and then those drops of water fall back into the water during a later cycle.  Will these drops of water impurify the clothes?  Is this excessive detail?
  4. If someone has wet feet and they walk on carpet or slippers on which there is something impure, is the impurity considered to have transferred onto their feet?{C}

If someone prays at home intentionally then is it sunnah for him to repeat the same salaah after he has prayed?

Q: One person said: "as praying in congregation is a strong sunnah, and although its intentionally abandoning is makruh tahrimi , the ulama said its repeating is sunnah." Does this mean if some does pray at home intentionally then it is sunnah for him to repeat the same salaah after he has prayed?