Hi babe, I'd recommend Yun Wei Catering for caterer as their food is delicious and service is awesome! I engaged them for my ROM last year and they are very flexible with the timing to come back to clear up the place. For the solemnisation venue depends on whether you like it indoor or outdoor because ours was quite simple as we held it at our place function room and invited only family and solemniser.
Not sure if you'll be interested.. If you want somewhere unique with nice outdoor scenery, how about on a boat/ferry? You can probably cater food on if needed.
Or do a getaway at one of the local more private islands like St John/Lazarus.