I think the answer is quite easy.

A SQ F award seems to be in order. I don't know why you would bother with a NW/CO/DL J award. They do fly to Male, Maldives as mentioned in your other thread. Something like JFK-FRA-SIN-Male would be great in F, giving you the Skysuite all the way to Singapore. You could even throw a few days in SIN for a little shopping too.

I'd start by going to the Singapore Airlines Krisflyer Forum and start doing a little research. I believe Megatop Lover is experienced in booking SQ award travel with DL miles.