Family of two + toddler visiting Japan in January 2026. I’ve read that it’s recommended to have a return ticket before arrival. But I’m trying to snag a last minute biz ticket from TYO back to the U.S. while traveling.
Want to buy a placeholder ticket but not sure if below are feasible. Options I’m considering:

• Book a fully refundable TYO→ICN ticket, or
  
• Use a 24-hour cancellation policy (book on United or Air Canada right before leaving the U.S. and cancel after clearing immigration).
  

Any tips?
For the actual return tickets I'm aiming to book two biz class or three economy with points. Can purchase economy right now, but do not want want to lock up points unnecessarily just in case I am able to find a biz class.
Thanks!