Hi Tigerlilly. I believe it is possible for you to bring your current helper to Singapore, but I believe the government takes a bigger cut of her salary than HK. Also, when you leave Singapore, she would most likely need to find re-employment here, and I know that doesn't always work well for people.
As far as where to live that really depends on your budget as much as what you want to do. Many expats live around the Holland Village/Botanic Gardens areas, but the rents are very high. I now live on the East Coast and love it. You're right by the beach and it just seems a little quieter on this side of Singapore. There are good areas around Novena-Bishan too. I wouldn't want to live around Orchard as there are always massive construction works and it's really noisy. Also more dangerous with little kids and the busy traffic.
Given your husband will be working around Harbourfront, check out Riverplace
condo on Havelock Drive. Very nice and convenient location. It's also close to UE Square (where there is a supermarket and a kindergym place).
I agree with the suggestion to do a
Serviced Apartment and then decide what you want. We stayed in the Somerset Grand Cairnhill when we arrived and it was really good. Big apartments and very central location.
I have also employed a part-time cleaner who has been brilliant. Not sure if she would consider full-time, but she may be able to recommend someone. If you want to contact her, please PM me.