1. You can use it. It’s just a change of language, the meaning doesn’t change. Yes you can’t use in kalima or takbeer.
2. Yes they elaborate this of prophet :
یا علی ان اللہ اید بک النبیین سرا و ایدنی بک جھرا۔
O Ali Allah has supported the prophets by you secretly and supported me openly.
حلية الابرار ج٢ ص ١٧