If we consider Fincare's response, then you should be safe. All you need to do is update your AU Bank details in Fincare FDs. Or maybe these guys will figure it out gradually (as now Fincare and AU share the same customer database) and request you to link both accounts.
I desperately want this to be true; otherwise, I will have to close my account (I am not eligible to open AU Digital 0 balance savings account, since this is only for new customers and now AU & Fincare databases are merged, I am not eligible to open this 0 balance account).
I purposefully opened the account in Fincare since I needed a 0 balance account for my daily UPI transactions. Also, opening an FD helped me with their attractive interest rate, which further upgraded my debit card to "RuPay Platinum," that too without paying any annual charges.
LTF RuPay Platinum debit card + 9% FD interest + 0 balance account + no hidden charges --> What else do you need in a savings bank account 🙂
Sure, I have attached my email conversation with them.
Feel free to spot if I have missed anything.