Hi all. About to book my first Star int'l reservation with CO. Is this legal?

CHOICE A
JFK-LAX <stopover>
LAX-ICN-HAN <destination>
HAN-SIN-ICN-JFK

I'm worried that the trip home via SIN & ICN is backtracking. So if not that, how about this:

CHOICE B
JFK-LAX <stopover>
LAX-ICN-HAN <destination / open jaw>
BKK-ICN-JFK

Would this help?

CHOICE C
LAX-ICN-HAN <destination / open jaw>
BKK-ICN-JFK <return to different city>

Thanks, all!
David