I gave birth at Mt. Alvernia via normal delivery with vacuum (1 bedder room). Our bill was around 10k. I think if normal delivery, not assisted and if you choose the cheapest room, 7k will be enough. You can sign up for maternity tour so you can see the rooms.
Hi. You can actually call KKH. They will be able to provide you witg information. However, here is an article. https://transferwise.com/gb/blog/cost-of-having-a-baby-in-singapore
For pass holders, public hospitals may not be cheaper than private. The most affordable private hospitals are Thomson and Mount Alvernia