Edit Narshe Esper battle

You can use Zone Doctor to look at the event code, but you CANNOT save with it. Well, you can, but you mustn't, for it will irreparably ruin your ROM. I don't know how FF6Tools handles event modification.

The soldiers DO respawn once each; when defeated, they set an event bit that marks them as such, then they get moved back to their start spot. When defeated a second time, they are deleted. To make them respawn indefinitely, you'd need to stop the game from setting those event bits ($FD is the hex code to NOP out event bit sets/clears. The event bit altering commands are two bytes each).

As for making the soldiers move more quickly, you could just increase their movement speed in the action queue (to Faster or Fastest). As Gi said, that movement code is controlled by the entrance event for the Narshe battlefield; you can get this event address in either Zone Doctor or FF6LE, just add $CA0000 to the number displayed on the Events tab.