I think best way to do so in BP it to pass object containing arrays and access arrays from object refrence, or access it from other means, for example if your Spawn BP is GameMode simply use to access node to access current GameMode cast it to your class and access array.
If your array don’t change during game (single level.match), i don’t see anything wrong by simply copy array (simply by setting array varable in spawned actor), at most you probbaly only gonna waste few or tens KBs of memory