If a modded starting system was not used the player's starting leaders will always be 0 (ruler), 1 (governor) and 2-5 (scientists).
If a modded starting system was not used the player's species will always be 0 for the main species and 1 for the syncretic/cyborg/bio-trophy/prepatent species. Species, leader, empire and pop IDs however are defined when the game is created and have to be found with the debugtooltip command.
Most IDs are predefined and can be found on the ID page.
