HitPay have lower fees than PayPal.

Nope, Sukas does not. The donations are sent to the payment provider (HitPay) and they will payout to Sukas.

Yep! Your input name and message will be shown on screen as per normal.

StreamElements was setup in USD, hence it would be more accurate to have the donations in USD. The donation itself would still be sent and recieved by Sukas in SGD.

The USD-SGD exchange rate is fixed at 1.336226 and is adjusted when there is a huge change in the average.
This value is the daily average exchange rate between 1 Jan 2023 - 30 June 2023 (ofx.com). It is a simple gauge to convert USD to SGD.