I would think its an exceedingly low chance of success to get 5 low level tickets like that. You also have to take into account the Korean Air blackout periods. If there is any KE route that is blacked out for a certain time, then DL blacks all of the KE flights out for that period. Mid summer has historically been a blackout for KE in for US-South America. If any one segment doesn't price low, then it breaks the whole thing.

Add to that you're saying summer which is busier travel season, and we have no idea what the Delta award redemption rates or program are going to look like a year from now... doesn't sound good to me.