First, OP is on separate tickets. PNR's don't matter in this case and it's a big mistake, especially when overseas and if dealing with local personnel to make PNRs an issue. Tickets, tickets & tickets.

Second, While DL will usually reacommodate on no shows across multiple DL tickets, there is no longer any such policy. So, it's not something on which you can count and thus the risk remains.

Third, what OP did was smart. You take what you can get because DL's sole obligation in the first instance is to get him to LAX. As the reroute is OA, OP need not accept it and may certainly require that he be rerouted on the next DL flight with availability or take a refund (DOT rules), but as a practical matter, it is generally smarter to move towards your final destination.