Arshi speaks basic Urdu words, just the way Rubina speaks basic Hindi words. Anyone who has studied both languages in school can figure them out.
Not sure why you bought Aly into this; I don’t see any issues with the way he speaks. This goes for the rest of the housemates. Some exceptions could be Nikki Tamboli who sometimes says phrases like “Main aapke baare mein KYA HI boloon.” No one uses KYA HI while speaking standard Hindi or Urdu. She translates that from Marathi - “Mi tujhya baddal KAHICH bolu.”
Urdu and Hindi as standard languages are derivatives or registers of Khari boli. Unless or otherwise you are using MISAALI ALFAAZ or THET SHABD while speaking, you aren’t differentiating much between the two languages. Their vocabularies are interchangeable.
Also, the language used by common people in India (and in Bollywood) is Hindustani. Urdu is used for Bollywood songs. Hindi is mostly used in parliamentary sessions (compare the way Smriti Malhotra Irani speaks to the language used in Bollywood movies).
Takabbur, Quwwat, Auqaat
Sandarbh, Anushaasan, Ninda
.... are all basic Urdu and Hindi words.