If I am remembering correctly, the crews stood in early 4-4-0's, so they wouldn't have seats.
Arttista makes some period-appropriate engineer and fireman figures:
#1531 Early engineer (seated)
#1532 (Period) Fireman Holding Wood
#1533 Period Engineer on One Knee
#1534 Period Fireman with Shovel (for coal burners)
#1554 Early engineer standing
Andy