Consider Korean Airlines for one way. I just checked a random date this summer. LAX-SGN is 75K in business class. You're allowed a stopover at the connection point which obviously is Seoul. Ultimate reward points can be moved into Korean Airlines as can Starwood points. Your 200K UR points plus 20K SPG points (that are given a 5K bonus on moving them) give you 225K points. It takes a while to set up a family account so if you have any thoughts at all of wanting to do this start earlier rather than later. You have to provide proof of the marriage. I think they took a copy of the deed to our house as proof of our marriage. It's extremely easy to find Korean award availability when using Korean miles. Also, the lovely people at their reservation line have endless patience and will allow bookings to be held for months which waiting to move points in.
It would be helpful if you gave your originating airport. My suggestion might not make any sense at all for you if you are not near an airport that Korean serves.