hi belinda (bmk). I'm from SFX, so I may be able to help. The church florist is pretty good. As far as I know, two people do it as a team. The guy in the team is a friend of mine, who works as a creative whatchmacallit at a landscape firm. (sorry, have no idea what his job title is!)
He does all the church decorations at Christmas time including the creche (ie the the bit at the side where you see the Holy Family and Baby Jesus).
It costs about $350 for the
1) altar arrangements
2) lectern arrangements
3) bride and groom's chair arrangements
and another $10 per small posy for each pew decorated. On average, most couples opt for two columns of 14 pews each from the altar, and alternate the posies such that you pay about $140 more.
Any further details, you'll prob need to speak to them yourself. Aunty Betty the parish secretary can give you their contact.
With regard to church choir, it depends on how much you want to pay and how stringent you are about your music.
Aunty Mabel is an organist who doesn't ask for a price, and she's really easygoing, but you may want to hear her playing first. You may not appreciate her style. She often can help you find a cantor to lead and sing in the microphone, also at no charge. Any hongbao is appreciated though. No choir at her disposal though. She's a piano teacher by trade.
The other choir, if you have a hefty budget, is Denis Leong's choir. They're a youth choir and they sing for saturday evening mass. Their asking price is pretty high though.
John Goh, one of the basses in the choir also has a group that does gregorian chants for a VERY DIFFERENT music style. PM me if you're interested.
otherwise, can't really help you. hope all this is useful!