Giving your IC number already can check already. Unless u they conlanfirm hire u, then different story of giving ur ic.
Think about it, why would they want to keep a copy of ur IC? During interview, they just need to check whether the info tally or not with the copy.

As for ur payslip - they just want to low ball u... No u are getting x amount and if u are asking more than 40% of market rate, this would enable HR to nego nego lor.
Know ur value and how much they need to pay lor.