Well, I don't know too much about Hindi or Urdu, but I don't think that there are lots of similarities between them and Arabic. But what I know is that there are some borrowed words in Hindi and Urdu from Arabic I usually hear it in their movies. Besides Arabic and Urdu have the same Alphabets scripts but no similarities with neither grammars nor words' meanings.
I think Urdu and Farsi are quite closer to each other than to Arabic.