2. As mentioned above, there is no need to pay the provident fund at all, and neither individuals nor enterprises need to pay it.
3. For people above EP, there is no mandatory insurance, and they can pay or not. If you hire SP, you must pay taxes to the government, hundreds of Singapore dollars per month.
I don't know if you are an employee or an employer. If the enterprise is too small, you can't hire foreign employees at all, because the government won't grant work permits.
If you have any questions, please keep asking questions.